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			22,846		22,846
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards		282			282
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in Shares)	66
Tax benefits from share-based payment arrangement exercises		146			146
Share-based payment arrangement compensation expense		862			862
Dividends on common stock			(1,937)		(1,937)
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 Sep. 30, 2013	332	83,969	267,258		351,559
Balance (in Shares) at Sep. 30, 2013	33,230
Balance at Jun. 30, 2013
Net income			7,301		7,301
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards	1	843			844
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in Shares)	71
Tax benefits from share-based payment arrangement exercises		43			43
Share-based payment arrangement compensation expense		222			222
Dividends on common stock			(832)		(832)
Balance at Dec. 31, 2013	333	85,077	273,727		359,137
Balance (in Shares) at Dec. 31, 2013	33,301
Net income			20,865		20,865
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards	1	1,054			1,055
Issuance of common stock from share-based payment arrangement exercises and vesting of performance unit awards (in Shares)	105
Tax benefits from share-based payment arrangement exercises		141			141
Share-based payment arrangement compensation expense		720			720
Dividends on common stock			(2,504)		(2,504)
Balance at Sep. 30, 2014	$ 334	$ 86,992	$ 292,088		$ 379,414
Balance (in Shares) at Sep. 30, 2014	33,406