Consolidated Statement of Stockholders' Equity - 6 months ended Jun. 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
Net income	82,124	$ 0	0	82,124	0	0
Other comprehensive income (loss), net of tax	(21,357)	$ 0	0	0	(21,357)	0
Treasury Stock, Value, Acquired, Cost Method	(34,662)					(34,662)
Stock Issued During Period, Shares, Employee Stock Purchase Plans		32
Stock Issued During Period, Value, Employee Stock Purchase Plan	1,119	$ (1)	10,672	0	0	(9,552)
Stock-based compensation	10,863	0	10,863	0	0	0
Tax effect from options exercised and the vesting of restricted shares			1,439
Cash dividends	(9,708)	0	0	(9,708)	0	0
Ending balance at Jun. 30, 2015	$ 1,004,151	$ 258	$ 287,045	$ 924,473	$ (103,341)	$ (104,284)
Ending balance, shares at Jun. 30, 2015		25,756