Consolidated Statements Of Shareholders' Equity - 3 months ended Mar. 31, 2016 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balances, shares at Dec. 31, 2015	50,178	50,178
Balances, value at Dec. 31, 2015	$ 1,321,904	$ 5,018	$ 624,997	$ 704,905	$ (13,016)
Stock-based compensation expense	$ 2,113	$ 0	2,113	0	0
Shares repurchased and retired, shares	(690)	(690)
Shares repurchased and retired, value	$ (14,205)	$ (69)	(7,536)	(6,600)	0
Stock options exercised, shares	47	47
Stock options exercised, value	$ 763	$ 4	759	0	0
Vesting of restricted stock units, shares	149	149
Vesting of restricted stock units, value	$ 0	$ 15	(15)	0	0
Shares withheld for taxes, shares	(20)	(20)
Shares withheld for taxes, value	$ (440)	$ (2)	(438)	0	0
Excess tax benefit of stock-based compensation	114	0	114	0	0
Comprehensive income	$ 10,162	$ 0	0	11,052	(890)
Balances, shares at Mar. 31, 2016	49,664	49,664
Balances, value at Mar. 31, 2016	$ 1,320,411	$ 4,966	$ 619,994	$ 709,357	$ (13,906)