Consolidated Statement of Stockholders' Equity - 6 months ended Jun. 30, 2016 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in-Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance, shares at Dec. 31, 2015		25,706
Beginning balance at Dec. 31, 2015	$ 918,252	$ 257	$ 291,092	$ 926,169	$ (137,984)	$ (161,282)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	80,871	0	0	80,871	0	0
Other comprehensive income (loss), net of tax	(16,420)	0	0	0	(16,420)	0
Treasury Stock, Value, Acquired, Cost Method	(115,246)	$ 0	0	0	0	(115,246)
Stock Issued During Period, Shares, Employee Stock Purchase Plans		(4)
Stock Issued During Period, Value, Employee Stock Purchase Plan	135	$ 0	16,261	0	0	16,396
Stock-based compensation	10,056	0	10,056	0	0	0
Cash dividends	(10,096)	$ 0	0	(10,096)	0	0
Ending balance, shares at Jun. 30, 2016		25,702
Ending balance at Jun. 30, 2016	$ 867,552	$ 257	284,887	$ 996,944	$ (154,404)	$ (260,132)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation			$ (85)