New Accounting Pronouncements - Cumulative Effect on Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Balance Sheet
Other assets - Deferred income taxes	$ 80,612	$ 392,987	$ 390,943
Current liabilities - Accrued expenses	204,656	137,382	125,688
Stockholders’ equity - Accumulated deficit	(967,949)	(1,061,468)	$ (1,051,818)
ASU 2014-09 | Balances Without Adoption of ASC 606
Balance Sheet
Other assets - Deferred income taxes	78,953
Current liabilities - Accrued expenses	191,404
Stockholders’ equity - Accumulated deficit	(956,418)
ASU 2014-09 | Effect of Change Higher / (Lower)
Balance Sheet
Other assets - Deferred income taxes	1,659	2,044
Current liabilities - Accrued expenses	13,252	11,694
Stockholders’ equity - Accumulated deficit	$ (11,531)	$ (9,650)