Consolidated Statements of Shareholders' Deficit Statement - USD ($) $ in Thousands		Total	Common Stock	Additional Paid-in- Capital	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Retained Earnings
Beginning balance (in shares) at Dec. 31, 2017			56,679,968
Beginning balance at Dec. 31, 2017		$ (258,601)	$ 951	$ 182,448	$ (4,699)	$ (1,064,573)	$ 627,272
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		25,086					25,086
Other comprehensive income		1,070			1,070
Share based payment activity (in shares)			498,510
Share based payment activity		26,579		13,203		13,376
Dividends declared ($0.215 per share)		(12,182)					(12,182)
Treasury purchases (in shares)			(517,839)
Treasury purchases		(41,869)				(41,869)
Ending balance at Mar. 31, 2018		$ (259,917)	$ 951	195,651	(3,629)	(1,093,066)	640,176
Ending balance (in shares) at Mar. 31, 2018			56,660,639
Beginning balance (in shares) at Dec. 31, 2018		55,679,207	55,679,207
Beginning balance at Dec. 31, 2018		$ (183,772)	$ 951	213,170	(5,446)	(1,187,625)	795,178
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		30,081					30,081
Other comprehensive income		8			8
Other	[1]	(614)					(614)
Share based payment activity (in shares)			408,545
Share based payment activity		12,920		3,214		9,706
Dividends declared ($0.215 per share)		$ (12,149)					(12,149)
Treasury purchases (in shares)		(354,646)	(414,077)
Treasury purchases		$ (31,951)				(31,951)
Ending balance at Mar. 31, 2019		$ (185,477)	$ 951	$ 216,384	$ (5,438)	$ (1,209,870)	$ 812,496
Ending balance (in shares) at Mar. 31, 2019		55,673,675	55,673,675

[1] Impact of adoption of Financial Accounting Standards Board ("FASB") Accounting Standards Update (“ASU”) No. 2014-09, Revenue From Contracts with Customers (Topic 606) and subsequent amendments to the initial guidance ("Topic 606") related to a foreign joint venture accounted for as an equity method investment.