Annual report pursuant to Section 13 and 15(d)

Income Taxes (Tax Effects of Temporary Differences) (Details)

v3.6.0.2
Income Taxes (Tax Effects of Temporary Differences) (Details) - USD ($)
$ in Thousands
Dec. 31, 2016
Dec. 31, 2015
Deferred tax assets:    
Net operating loss carryforwards $ 111,236 $ 139,238
Deferred revenue for financial reporting purposes 59,993 41,151
Asset retirement obligations in excess of amounts recognized for tax purposes 16,808 14,338
Compensated absences accrued for financial reporting purposes 3,505 3,339
Share-based compensation expense for financial reporting purposes in excess of amounts recognized for tax purposes 3,393 2,773
Accounts receivable, principally due to allowance for doubtful receivables 1,965 1,912
Workers compensation and self-insurance health reserves, principally due to accrual for financial reporting purposes 1,705 1,795
Alternative minimum tax credits 1,735 1,735
Deferred compensation expense for tax purposes in excess of amounts recognized for financial reporting purposes 1,687 1,603
Other 11,515 13,144
Total deferred tax assets 213,542 221,028
Deferred tax liabilities:    
Plant and equipment, principally due to differences in depreciation 245,118 246,172
Intangible assets 106,061 79,255
Other 345 1,746
Total deferred tax liabilities 351,524 327,173
Net deferred tax liabilities $ 137,982 $ 106,145