Condensed Consolidated Statement Of Stockholders' Equity - 3 months ended Mar. 31, 2016 - USD ($) $ in Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings	Treasury Stock
Balance - December 31, 2015 at Dec. 31, 2015	$ 438,575	$ 270	$ 166,566	$ 301,206	$ (29,467)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	35,959			35,959
Issuance of 150,466 shares of common stock pursuant to stock-based awards, net of shares tendered for payment of taxes	(4,606)	2	(4,608)
Income tax benefit relating to issuance of common stock pursuant to stock-based awards	1,410		1,410
Stock-based compensation expense	3,140		3,140
Issuance of 4,784 deferred stock units relating to prior year compensation	264		264
Cash dividend ($0.30 per share)	(7,344)			(7,344)
Balance - March 31, 2016 at Mar. 31, 2016	$ 467,398	$ 272	$ 166,772	$ 329,821	$ (29,467)