New Accounting Pronouncements - Cumulative Effect on Balance Sheet (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 02, 2018	Jan. 01, 2018	Dec. 31, 2017
Other assets
Deferred income taxes	$ 388,058		$ 392,987		$ 390,943
Current liabilities
Accrued expenses	134,312		137,382		125,688
Shareholders' deficit
Retained deficit	(1,016,031)		$ (1,061,468)		$ (1,051,818)
Retrospective adjustments
Net cash provided by operating activities	66,937	$ 84,832
Net cash used in financing activities	64,423	31,543
Balances Without Adoption of ASC 606
Other assets
Deferred income taxes	386,271
Current liabilities
Accrued expenses	123,078
Shareholders' deficit
Retained deficit	(1,007,175)
ASU 2014-09 | Effect of Change Higher / (Lower)
Other assets
Deferred income taxes	1,787			$ 2,044
Current liabilities
Accrued expenses	11,234			11,694
Shareholders' deficit
Retained deficit	$ (8,856)			$ (9,650)
ASU 2016-15 | Adjustment
Retrospective adjustments
Net cash provided by operating activities		18,000
Net cash used in financing activities		$ 18,000