Annual report pursuant to Section 13 and 15(d)

Business and Summary of Significant Accounting Principles (Classification of Taxes Collected from Customers) (Details)

v3.8.0.1
Business and Summary of Significant Accounting Principles (Classification of Taxes Collected from Customers) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Accounting Policies [Abstract]      
Surcharges reported gross $ 3,226 $ 3,849 $ 5,058