Condensed Consolidated Statement Of Stockholders' Equity (USD $) In Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings	Treasury Stock
Balance - at Dec. 31, 2013	$ 313,613	$ 261	$ 126,360	$ 216,459	$ (29,467)
Net income	34,782			34,782
Issuance of 228,667 shares of common stock pursuant to stock options and deferred stock units	1,418	2	1,416
Income tax benefit relating to issuance of common stock pursuant to stock options and deferred stock units, net of shares tendered for payment	2,007		2,007
Stock-based compensation expense	5,277		5,277
Issuance of 43,188 deferred stock units relating to prior year compensation	1,986		1,986
Dividend equivalents on deferred stock units, stock awards and restricted stock			1,811	(1,811)
Balance - at Jun. 30, 2014	$ 359,083	$ 263	$ 138,857	$ 249,430	$ (29,467)