Consolidated Statement of Stockholders' Equity (Unaudited) - 9 months ended Sep. 30, 2015 - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2014	$ 600,634	$ 241	$ (94,074)	$ 442,308	$ 254,814	$ (2,655)
Beginning Balance, shares at Dec. 31, 2014		24,115,593	(2,109,316)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	43,391				39,709	3,682
Issuance of common stock in connection with:
Restricted stock awards, net of cancellations		$ 4	$ (1,971)	1,967
Restricted stock awards, net of cancellations, shares		404,525	(34,695)
Business acquisition	2,204			2,204
Business acquisition, shares		28,486
Share-based compensation	17,239			17,239
Shares redeemed for employee tax withholdings	(5,194)		$ (5,194)
Shares redeemed for employee tax withholdings, shares			(76,670)
Income tax benefit on share-based compensation	3,095			3,095
Share repurchases	(13,498)	$ (2)		(13,496)
Shares repurchased, shares		(217,279)
Ending Balance at Sep. 30, 2015	$ 647,871	$ 243	$ (101,239)	$ 453,317	$ 294,523	$ 1,027
Ending Balance, shares at Sep. 30, 2015		24,331,325.000	(2,220,681.000)