Consolidated Statements Of Shareholders' Equity - 6 months ended Jun. 30, 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	$ 3,981	$ 0	3,981	0	0
Shares repurchased and retired, shares	(1,440)	(1,440)
Shares repurchased and retired, value	$ (29,315)	$ (144)	(15,724)	(13,447)	0
Stock options exercised, shares	51	51
Stock options exercised, value	$ 823	$ 5	818	0	0
Vesting of restricted stock units, shares	171	171
Vesting of restricted stock units, value	$ 0	$ 17	(17)	0	0
Shares withheld for taxes, shares	(25)	(25)
Shares withheld for taxes, value	$ (535)	$ (3)	(532)	0	0
Excess tax benefit of stock-based compensation	(111)	0	(111)	0	0
Comprehensive income	$ 21,370	$ 0	0	23,737	(2,367)
Balances, shares at Jun. 30, 2016	48,935	48,935
Balances, value at Jun. 30, 2016	$ 1,318,117	$ 4,893	$ 613,412	$ 715,195	$ (15,383)