Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings
Balance (in shares) at Dec. 31, 2013		55,067
Balance at Dec. 31, 2013	$ 164,106	$ 221	$ 0	$ 163,885
Net income	44,158			44,158
Stock options exercised and restricted stock awards granted, including tax benefits (in shares)		463
Stock options exercised and restricted stock awards granted, including tax benefits	2,557	$ 1	2,556
Share-based compensation	2,178		2,178
Stock repurchased and retired (in shares)		(1,488)
Stock repurchased and retired	(29,284)	$ (6)	(4,734)	(24,544)
Dividends	(9,656)			(9,656)
Balance (in shares) at Dec. 31, 2014		54,042
Balance at Dec. 31, 2014	174,059	$ 216	0	173,843
Net income	45,728			45,728
Stock options exercised and restricted stock awards granted, including tax benefits (in shares)		546
Stock options exercised and restricted stock awards granted, including tax benefits	5,240	$ 2	5,238
Share-based compensation	2,891		2,891
Stock repurchased and retired (in shares)		(1,576)
Stock repurchased and retired	(37,143)	$ (6)	(8,129)	(29,008)
Dividends	(11,857)			(11,857)
Balance (in shares) at Dec. 31, 2015		53,012
Balance at Dec. 31, 2015	178,918	$ 212	0	178,706
Net income	53,376			53,376
Stock options exercised and restricted stock awards granted, including tax benefits (in shares)		375
Stock options exercised and restricted stock awards granted, including tax benefits	2,063	$ 2	2,061
Share-based compensation	4,357		4,357
Stock repurchased and retired (in shares)		(736)
Stock repurchased and retired	(20,140)	$ (3)	(6,418)	(13,719)
Dividends	(12,676)			(12,676)
Balance (in shares) at Dec. 31, 2016		52,651
Balance at Dec. 31, 2016	$ 205,898	$ 211	$ 0	$ 205,687