Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Stock Issued to Directors [Member] Common Stock [Member]	Stock Issued to Directors [Member] Additional Paid-in Capital [Member]	Stock Issued to Directors [Member]	Stock Issued for 401(K) Match [Member] Common Stock [Member]	Stock Issued for 401(K) Match [Member] Additional Paid-in Capital [Member]	Stock Issued for 401(K) Match [Member]	Series B Preferred Stock [Member] Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2013							$ 39	$ 85,896	$ 1,426,845	$ (154,982)	$ (26,299)	$ (5,080)	$ 1,326,419
Net income										17,824			17,824
Stock issued to directors	$ 37	$ 438	$ 475
Series B Preferred Stock dividends declared										(552)			(552)
Stock issued for 401(k) match				$ 203	$ 2,226	$ 2,429
Restricted stock units granted									9,019				9,019
Restricted stock unit distributions								665	(665)			(2,279)	(2,279)
Warrants exercised								5,577	48,841				54,418
Common stock dividends declared								4	46	(3,596)			(3,546)
Repurchase of common shares												(1,501)	(1,501)
Other comprehensive loss											(5,732)		(5,732)
Balance at Dec. 31, 2014							39	92,382	1,486,750	(141,306)	(32,031)	(8,860)	1,396,974
Net income										(86,968)			(86,968)
Stock issued to directors	59	547	606					218	2,808				3,026
Series B Preferred Stock dividends declared										(552)			(552)
Stock issued for 401(k) match				333	3,114	3,447		441	4,569				5,010
Restricted stock units granted									4,819				4,819
Restricted stock unit distributions								224	(224)			(934)	(934)
Common stock dividends declared										(3,739)			(3,739)
Repurchase of common shares												(940)	(940)
Other comprehensive loss											(600)		(600)
Balance at Dec. 31, 2015							39	95,219	1,519,598	(232,565)	(32,631)	(10,734)	1,338,926
Common stock issued for purchase of another company								1,562	17,215				18,777
Net income										69,547			69,547
Stock issued to directors	$ 47	$ 756	$ 803					545	5,188			(1,270)	4,463
Series B Preferred Stock dividends declared										(552)			(552)
Stock issued for 401(k) match				$ 282	$ 3,236	$ 3,518		457	7,230				7,687
Restricted stock units granted									5,128				5,128
Restricted stock unit distributions								348	(348)			(2,211)	(2,211)
Common stock dividends declared										(3,867)			(3,867)
Other comprehensive loss											(1,971)		(1,971)
Balance at Dec. 31, 2016							$ 39	99,806	1,597,212	$ (167,437)	$ (34,602)	(15,174)	1,479,844
Common stock issued for purchase of another company								2,213	48,998			$ (959)	50,252
Common stock issued for cash, net of offering costs								$ 695	$ 7,426				$ 8,121