Condensed Consolidated Stockholders' Equity Statement (Unaudited) - 9 months ended Sep. 30, 2018 - USD ($) shares in Thousands, $ in Thousands	Total	Mandatory Convertible Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Non-controlling Interest
Beginning balance (in shares) at Dec. 31, 2017		52	50,335			8,316
Beginning balance at Dec. 31, 2017	$ 1,434,866	$ 1	$ 503	$ 1,123,832	$ 833,610	$ (425,685)	$ (98,026)	$ 631
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting principles	(29,041)				(29,041)
Net income (loss)	117,220				117,368			(148)
Other comprehensive income, net of tax	12,352						12,359	(7)
Exercise of stock options, net of tax withholding forfeitures	(765)			(883)		$ 118
Exercise of stock options, net of tax withholding forfeitures (in shares)						20
Conversion of restricted stock units into common stock, net of tax withholding forfeitures	(1,239)			(1,907)		$ 668
Conversion of restricted stock units into common stock, net of tax withholding forfeitures (in shares)						48
Share repurchase program	$ (125,000)					$ (125,000)
Share repurchase program (in shares)	(1,800)					(1,782)
Share-based compensation	$ 14,657			14,657
Redemption of stockholders' rights agreement	(411)				(411)
Preferred stock dividends	(26,198)				(26,198)
Common stock dividends ($0.15 per share)	(6,139)				(6,139)
Ending balance (in shares) at Sep. 30, 2018		52	50,335			10,030
Ending balance at Sep. 30, 2018	$ 1,390,302	$ 1	$ 503	$ 1,135,699	$ 889,189	$ (549,899)	$ (85,667)	$ 476