Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings
Balance, beginning of period at Dec. 31, 2011	$ 161,542us-gaap_StockholdersEquity	$ 0	$ 122	$ 87,225	$ 74,195
Preferred stock, shares outstanding, beginning of period at Dec. 31, 2011		0
Common stock, shares outstanding, beginning of period at Dec. 31, 2011			12,179,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and warrants	180	0	0	180	0
Exercise of common stock options and warrants, shares		0	23,000
Compensation expense on common stock options	440	0	0	440	0
Issuance of restricted stock, shares		0	39,000
Issuance of restricted stock	0	0	0	0	0
Compensation expense on restricted common stock	978	0	0	978	0
Net income	12,685us-gaap_NetIncomeLoss				12,685
Balance, end of period at Dec. 31, 2012	175,825us-gaap_StockholdersEquity	0	122	88,823	86,880
Preferred stock, shares outstanding, end of period at Dec. 31, 2012		0
Common stock, shares outstanding, end of period at Dec. 31, 2012			12,241,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and warrants	829	0	0	829	0
Exercise of common stock options and warrants, shares		0	53,000
Compensation expense on common stock options	198	0	0	198	0
Issuance of restricted stock, shares		0	72,000
Issuance of restricted stock	0	0	0	0	0
Tax benefit of equity compensation	10			10
Compensation expense on restricted common stock	1,485	0	1	1,484	0
Net income	14,390us-gaap_NetIncomeLoss				14,390
Balance, end of period at Dec. 31, 2013	192,737us-gaap_StockholdersEquity	0	123	91,344	101,270
Preferred stock, shares outstanding, end of period at Dec. 31, 2013	0us-gaap_PreferredStockSharesOutstanding	0
Common stock, shares outstanding, end of period at Dec. 31, 2013	12,366,000us-gaap_CommonStockSharesOutstanding		12,366,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and warrants	59	0	0	59	0
Exercise of common stock options and warrants, shares		0	3,000
Compensation expense on common stock options	426	0	0	426	0
Issuance of restricted stock, shares		0	97,000
Issuance of restricted stock	0	0	0	0	0
Tax benefit of equity compensation	419			419
Compensation expense on restricted common stock	2,818	0	1	2,817	0
Net income	14,128us-gaap_NetIncomeLoss				14,128
Balance, end of period at Dec. 31, 2014	$ 210,587us-gaap_StockholdersEquity	$ 0	$ 124	$ 95,065	$ 115,398
Preferred stock, shares outstanding, end of period at Dec. 31, 2014	0us-gaap_PreferredStockSharesOutstanding	0
Common stock, shares outstanding, end of period at Dec. 31, 2014	12,466,000us-gaap_CommonStockSharesOutstanding		12,466,000

This element represents the amount of recognized equity-based compensation during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized). Alternate captions include the words "stock-based compensation".

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