Consolidated Statements of Stockholders Equity (USD $) In Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2008	$ 218	$ 75,305	$ 180,213	$ 1,715	$ 257,451
Balance (in Shares) at Dec. 31, 2008	21,830
Income before income taxes attributable to noncontrolling interest				584	584
Noncontrolling interest distributions				(568)	(568)
Net income			16,267		16,267
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards	1	331			332
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in Shares)	55
Tax benefits from share-based payment arrangement exercises		255			255
Share-based payment arrangement compensation expense		586			586
Balance at Dec. 31, 2009	219	76,477	196,480	1,731	274,907
Balance (in Shares) at Dec. 31, 2009	21,885
Income before income taxes attributable to noncontrolling interest				631	631
Noncontrolling interest distributions				(451)	(451)
Net income			19,742		19,742
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards	1	302			303
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in Shares)	65
Tax benefits from share-based payment arrangement exercises		385			385
Share-based payment arrangement compensation expense		1,264			1,264
Dividends on common stock			(877)		(877)
Balance at Dec. 31, 2010	220	78,428	215,345	1,911	295,904
Balance (in Shares) at Dec. 31, 2010	21,950
Income before income taxes attributable to noncontrolling interest				807	807
Noncontrolling interest distributions				(529)	(529)
Net income			24,285		24,285
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards		137			137
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in Shares)	35
Tax benefits from share-based payment arrangement exercises		164			164
Share-based payment arrangement compensation expense		1,349			1,349
Dividends on common stock			(1,758)		(1,758)
Balance at Dec. 31, 2011	$ 220	$ 80,078	$ 237,872	$ 2,189	$ 320,359
Balance (in Shares) at Dec. 31, 2011	21,985