| Segment Information (Tables)
 | 12 Months Ended | 
| Dec. 31, 2017 | 
|---|
| Segment Information |  | 
| Schedule of performance measures |  
		
			Performance Measures
		 
			
				| 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  |  
				| 
						  | 
						  | 
						Years ended December 31, | 
						  |  
				| 
						  | 
						  | 
						2017 | 
						  | 
						2016 | 
						  | 
						2015 | 
						  |  
				| 
						  | 
						  | 
						  | 
						  | 
						  | 
						Adjusted | 
						  | 
						  | 
						  | 
						Adjusted | 
						  | 
						  | 
						  | 
						Adjusted | 
						  |  
				| 
						  | 
						  | 
						Revenue | 
						  | 
						OIBDA | 
						  | 
						Revenue | 
						  | 
						OIBDA | 
						  | 
						Revenue | 
						  | 
						OIBDA | 
						  |  
				| 
						  | 
						  | 
						amounts in thousands | 
						  |  
				| 
						Skyhook  | 
						     | 
						$ | 
						 13,092 | 
						     | 
						 (9,496) | 
						     | 
						 30,586 | 
						     | 
						 (2,681) | 
						     | 
						 91,182 | 
						     | 
						 43,600 | 
						  |  
				| 
						Charter  | 
						  | 
						  | 
						 41,581,000 | 
						  | 
						 14,955,000 | 
						  | 
						 29,003,000 | 
						  | 
						 9,607,000 | 
						  | 
						 9,754,000 | 
						  | 
						 3,317,000 | 
						  |  
				| 
						Corporate and other | 
						  | 
						  | 
						  — | 
						  | 
						 (6,920) | 
						  | 
						— | 
						  | 
						 (8,761) | 
						  | 
						— | 
						  | 
						 (11,958) | 
						  |  
				| 
						  | 
						  | 
						  | 
						 41,594,092 | 
						  | 
						 14,938,584 | 
						  | 
						 29,033,586 | 
						  | 
						 9,595,558 | 
						  | 
						 9,845,182 | 
						  | 
						 3,348,642 | 
						  |  
				| 
						Eliminate equity method affiliate | 
						  | 
						  | 
						 (41,581,000) | 
						  | 
						 (14,955,000) | 
						  | 
						 (29,003,000) | 
						  | 
						 (9,607,000) | 
						  | 
						 (9,754,000) | 
						  | 
						 (3,317,000) | 
						  |  
				| 
						Consolidated Liberty Broadband | 
						  | 
						$ | 
						 13,092 | 
						  | 
						 (16,416) | 
						  | 
						 30,586 | 
						  | 
						 (11,442) | 
						  | 
						 91,182 | 
						  | 
						 31,642 | 
						  | 
			 
		 | 
| Schedule of segment reporting information |  
		
			Other Information
		 
			
				| 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  |  
				| 
						  | 
						  | 
						December 31, 2017 | 
						  | 
						December 31, 2016 | 
						  |  
				| 
						  | 
						  | 
						Total | 
						  | 
						Investments | 
						  | 
						Capital | 
						  | 
						Total | 
						  | 
						Investments | 
						  | 
						Capital | 
						  |  
				| 
						  | 
						  | 
						assets | 
						  | 
						in affiliates | 
						  | 
						expenditures | 
						  | 
						assets | 
						  | 
						in affiliates | 
						  | 
						expenditures | 
						  |  
				| 
						  | 
						  | 
						amounts in thousands | 
						  |  
				| 
						Skyhook  | 
						     | 
						$ | 
						 24,481 | 
						     | 
						  — | 
						     | 
						 70 | 
						     | 
						 30,463 | 
						     | 
						  — | 
						     | 
						 267 | 
						  |  
				| 
						Charter | 
						  | 
						  | 
						 146,623,000 | 
						  | 
						  — | 
						  | 
						 8,681,000 | 
						  | 
						 149,067,000 | 
						  | 
						  — | 
						  | 
						 5,325,000 | 
						  |  
				| 
						Corporate and other | 
						  | 
						  | 
						 11,907,308 | 
						  | 
						 11,835,613 | 
						  | 
						  — | 
						  | 
						 9,560,497 | 
						  | 
						 9,315,253 | 
						  | 
						  — | 
						  |  
				| 
						  | 
						  | 
						  | 
						 158,554,789 | 
						  | 
						 11,835,613 | 
						  | 
						 8,681,070 | 
						  | 
						 158,657,960 | 
						  | 
						 9,315,253 | 
						  | 
						 5,325,267 | 
						  |  
				| 
						Eliminate equity method affiliate | 
						  | 
						  | 
						 (146,623,000) | 
						  | 
						  — | 
						  | 
						 (8,681,000) | 
						  | 
						 (149,067,000) | 
						  | 
						  — | 
						  | 
						 (5,325,000) | 
						  |  
				| 
						Consolidated Liberty Broadband | 
						  | 
						$ | 
						 11,931,789 | 
						  | 
						 11,835,613 | 
						  | 
						 70 | 
						  | 
						 9,590,960 | 
						  | 
						 9,315,253 | 
						  | 
						 267 | 
						  | 
			 
		 | 
| Schedule of revenue by geographic area |  
		
			
				| 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  |  
				| 
						  | 
						  | 
						Years ended December 31, | 
						  |  
				| 
						  | 
						  | 
						2017 | 
						  | 
						2016 | 
						  | 
						2015 | 
						  |  
				| 
						  | 
						  | 
						amounts in thousands | 
						  |  
				| 
						United States | 
						     | 
						$ | 
						 10,315 | 
						     | 
						 27,806 | 
						     | 
						 87,739 | 
						  |  
				| 
						Other countries | 
						  | 
						  | 
						 2,777 | 
						  | 
						 2,780 | 
						  | 
						 3,443 | 
						  |  
				| 
						  | 
						  | 
						$ | 
						 13,092 | 
						  | 
						 30,586 | 
						  | 
						 91,182 | 
						  | 
			 
		 | 
| Schedule of reconciliation of segment Adjusted OIBDA to earnings (loss) before income taxes |  
		
			
				| 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  | 
						  |  
				| 
						  | 
						  | 
						Years ended December 31, | 
						  |  
				| 
						  | 
						  | 
						2017 | 
						  | 
						2016 | 
						  | 
						2015 | 
						  |  
				| 
						  | 
						  | 
						amounts in thousands | 
						  |  
				| 
						Consolidated segment Adjusted OIBDA | 
						     | 
						$ | 
						 (16,416) | 
						     | 
						 (11,442) | 
						     | 
						 31,642 | 
						  |  
				| 
						Stock-based compensation | 
						  | 
						  | 
						 (5,292) | 
						  | 
						 (5,713) | 
						  | 
						 (6,380) | 
						  |  
				| 
						Depreciation and amortization | 
						  | 
						  | 
						 (3,770) | 
						  | 
						 (4,005) | 
						  | 
						 (6,088) | 
						  |  
				| 
						Gain on legal settlement | 
						  | 
						  | 
						  — | 
						  | 
						  — | 
						  | 
						 60,450 | 
						  |  
				| 
						Impairment of intangible assets | 
						  | 
						  | 
						  — | 
						  | 
						  — | 
						  | 
						 (20,669) | 
						  |  
				| 
						Operating income (loss)  | 
						  | 
						  | 
						 (25,478) | 
						  | 
						 (21,160) | 
						  | 
						 58,955 | 
						  |  
				| 
						Interest expense | 
						  | 
						  | 
						 (19,570) | 
						  | 
						 (14,956) | 
						  | 
						 (7,424) | 
						  |  
				| 
						Dividend and interest income | 
						  | 
						  | 
						 1,449 | 
						  | 
						 5,020 | 
						  | 
						 3,797 | 
						  |  
				| 
						Share of earnings (loss) of affiliates, net | 
						  | 
						  | 
						 2,508,991 | 
						  | 
						 641,544 | 
						  | 
						 (120,962) | 
						  |  
				| 
						Realized and unrealized gains (losses) on financial instruments, net | 
						  | 
						  | 
						 3,098 | 
						  | 
						 94,122 | 
						  | 
						 2,619 | 
						  |  
				| 
						Gain (loss) on dilution of investment in affiliate | 
						  | 
						  | 
						 (17,872) | 
						  | 
						 770,766 | 
						  | 
						 (7,198) | 
						  |  
				| 
						Other, net | 
						  | 
						  | 
						 (18) | 
						  | 
						 336 | 
						  | 
						 158 | 
						  |  
				| 
						Earnings (loss) from continuing operations before income taxes | 
						  | 
						$ | 
						 2,450,600 | 
						  | 
						 1,475,672 | 
						  | 
						 (70,055) | 
						  | 
			 
		 |