CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Total
Balance at Dec. 31, 2011	$ 191	$ 33,179	$ 145,688	$ (48,542)	$ 130,516
Balance (in shares) at Dec. 31, 2011	16,138,158
Increase (Decrease) in Stockholders' Equity
Exercise of stock options		(183)		236	53
Exercise of stock options (in shares)	9,166
Stock based compensation expense		1,368			1,368
Net income			8,911		8,911
Balance at Dec. 31, 2012	191	34,364	154,599	(48,306)	140,848
Balance (in shares) at Dec. 31, 2012	16,147,324
Increase (Decrease) in Stockholders' Equity
Exercise of stock options		(5,071)		8,509	3,438
Exercise of stock options (in shares)	335,444
Excess tax benefit from stock-based compensation		413			413
Stock based compensation expense		1,220			1,220
Net income			17,961		17,961
Balance at Dec. 31, 2013	191	30,926	172,560	(39,797)	163,880
Balance (in shares) at Dec. 31, 2013	16,482,768				16,482,768
Increase (Decrease) in Stockholders' Equity
Excess tax benefit from stock-based compensation		386			386
Net exercise of stock options, including related tax benefit		(9,553)		6,827	(2,726)
Net exercise of stock options, including related tax benefit (in shares)	330,026
Stock based compensation expense		1,226			1,226
Net income			14,185		14,185
Balance at Dec. 31, 2014	$ 191	$ 22,985	$ 186,745	$ (32,970)	$ 176,951
Balance (in shares) at Dec. 31, 2014	16,812,794				16,812,794