Consolidated Statements Of Shareholders' Equity - 9 months ended Sep. 30, 2015 - 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, 2014	52,994	52,994
Balances, value at Dec. 31, 2014	$ 1,289,625	$ 5,300	$ 649,715	$ 644,085	$ (9,475)
Stock-based compensation expense	6,021	$ 0	6,021	0	0
Shares repurchased and retired, shares		(2,296)
Shares repurchased and retired, value	$ (52,323)	$ (230)	(25,068)	(27,025)	0
Stock options exercised, shares	94	94
Stock options exercised, value	$ 1,683	$ 9	1,674	0	0
Vesting of restricted stock units, net of restricted share forfeitures, shares		150
Vesting of restricted stock units, net of restricted share forfeitures, value	0	$ 15	(15)	0	0
Shares withheld for taxes, shares		(24)
Shares withheld for taxes, value	(571)	$ (2)	(569)	0	0
Excess tax benefit of stock-based compensation	307	0	307	0	0
Comprehensive income	$ 53,561	$ 0	0	55,980	(2,419)
Balances, shares at Sep. 30, 2015	50,918	50,918
Balances, value at Sep. 30, 2015	$ 1,298,303	$ 5,092	$ 632,065	$ 673,040	$ (11,894)