Consolidated Statement of Stockholders' Equity - 9 months ended Sep. 30, 2015 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in-Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2014	$ 978,010	$ 257	$ 286,854	$ 852,057	$ (81,984)	$ (79,174)
Beginning balance, shares at Dec. 31, 2014		25,724
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	127,385	$ 0	0	127,385	0	0
Other comprehensive income (loss), net of tax	(63,821)	0	0	0	(63,821)	0
Treasury Stock, Value, Acquired, Cost Method	(72,664)	$ 0	0	0	0	(72,664)
Stock Issued During Period, Shares, Employee Stock Purchase Plans		(3)
Stock Issued During Period, Value, Employee Stock Purchase Plan	795	$ 0	14,052	0	0	(13,257)
Stock-based compensation	15,952	0	15,952	0	0	0
Tax effect from options exercised and the vesting of restricted shares			1,827
Cash dividends	(14,739)	0	0	(14,739)	0	0
Ending balance at Sep. 30, 2015	$ 969,328	$ 257	$ 288,754	$ 964,703	$ (145,805)	$ (138,581)
Ending balance, shares at Sep. 30, 2015		25,721