Consolidated Condensed Statements of Stockholders' Equity (Unaudited) (USD $) In Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]	Total
Balance at Dec. 31, 2012	$ 332	$ 82,679	$ 246,349	$ 2,563	$ 331,923
Balance (in Shares) at Dec. 31, 2012	33,164
Net income			7,202		7,202
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards		22			22
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in Shares)	18
Share-based payment arrangement compensation expense		217			217
Dividends on common stock			(553)		(553)
Income before income taxes attributable to noncontrolling interest				84	84
Noncontrolling interest distributions				(84)	(84)
Change to equity method of accounting				(2,563)	(2,563)
Balance at Mar. 31, 2013	332	82,918	252,998		336,248
Balance (in Shares) at Mar. 31, 2013	33,182
Net income			22,945		22,945
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards	1	1,103			1,104
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in Shares)	119
Tax benefits from share-based payment arrangement exercises		189			189
Share-based payment arrangement compensation expense		867			867
Dividends on common stock			(2,216)		(2,216)
Balance at Dec. 31, 2013	333	85,077	273,727		359,137
Balance (in Shares) at Dec. 31, 2013	33,301
Net income			5,287		5,287
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards		370			370
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in Shares)	48
Tax benefits from share-based payment arrangement exercises		50			50
Share-based payment arrangement compensation expense		211			211
Dividends on common stock			(834)		(834)
Balance at Mar. 31, 2014	$ 333	$ 85,708	$ 278,180		$ 364,221
Balance (in Shares) at Mar. 31, 2014	33,349