Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income
Beginning Balance (in shares) at Dec. 31, 2013		94,072
Beginning Balance at Dec. 31, 2013	$ 815,579	$ 112	$ (733,155)	$ 846,559	$ 700,108	$ 1,955
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	250,088				255,872	(5,784)
Purchase of treasury stock (in shares)		(6,671)
Purchase of treasury stock	(283,226)		(283,226)
Dividends declared	(57,406)				(57,406)
Exercise of stock options (in shares)		970
Exercise of stock options	22,171	$ 1		22,170
Restricted stock awards (in shares)		(18)
Restricted stock awards	0			0
Minimum tax withholding requirements (in shares)		(18)
Minimum tax withholding requirements	(762)			(762)
Excess tax benefit from stock-based compensation	3,743			3,743
Stock-based compensation	5,856			5,856
Ending Balance (in shares) at Dec. 31, 2014		88,335
Ending Balance at Dec. 31, 2014	756,043	$ 113	(1,016,381)	877,566	898,574	(3,829)
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	213,479				219,299	(5,820)
Purchase of treasury stock (in shares)		(12,414)
Purchase of treasury stock	(479,799)		(479,799)
Dividends declared	(59,725)				(59,725)
Exercise of stock options (in shares)		80
Exercise of stock options	1,744	$ 1		1,743
Restricted stock awards (in shares)		290
Restricted stock awards	0			0
Minimum tax withholding requirements (in shares)		(15)
Minimum tax withholding requirements	(574)			(574)
Excess tax benefit from stock-based compensation	604			604
Stock-based compensation	6,280			6,280
Issuance of convertible senior notes, net	30,509			30,509
Ending Balance (in shares) at Dec. 31, 2015		76,276
Ending Balance at Dec. 31, 2015	468,561	$ 114	(1,496,180)	916,128	1,058,148	(9,649)
Increase (Decrease) in Stockholders' Equity
Comprehensive income (loss)	(285,298)				(286,250)	952
Purchase of treasury stock (in shares)		(7,926)
Purchase of treasury stock	(229,169)		(229,169)
Dividends declared	(55,700)				(55,700)
Exercise of stock options (in shares)		24
Exercise of stock options	353	$ 0		353
Restricted stock awards (in shares)		74
Restricted stock awards	0			0
Minimum tax withholding requirements (in shares)		(49)
Minimum tax withholding requirements	(1,169)			(1,169)
Excess tax benefit from stock-based compensation	(1,458)			(1,458)
Stock-based compensation	8,833			8,833
Ending Balance (in shares) at Dec. 31, 2016		68,399
Ending Balance at Dec. 31, 2016	$ (95,047)	$ 114	$ (1,725,349)	$ 922,687	$ 716,198	$ (8,697)