Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	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, 2017	$ 39	$ 100,926	$ 1,619,816	$ (218,089)	$ (23,373)	$ (18,042)	$ 1,461,277
Net (loss) income				8,240			8,240
Restricted stock units granted			1,089				1,089
Common stock dividends declared ($0.0025 per common share)				(998)			(998)
Series B Preferred Stock dividends declared ($0.875 per share)				(138)			(138)
Common stock issued for 401(k) match		55	839				894
Other comprehensive income (loss)					(2,105)		(2,105)
Change in accounting for marketable equity securities				1,289	(1,289)
Common stock issued for employee incentive compensation 1,237,369 shares)		309	4,554			(1,225)	3,638
Balance at Mar. 31, 2018	39	101,290	1,626,298	(209,696)	(26,767)	(19,267)	1,471,897
Balance at Dec. 31, 2018	39	121,956	1,880,481	(248,308)	(42,469)	(20,736)	1,690,963
Net (loss) income				(25,533)			(25,533)
Restricted stock units granted			1,579				1,579
Common stock dividends declared ($0.0025 per common share)				(1,209)			(1,209)
Series B Preferred Stock dividends declared ($0.875 per share)				(138)			(138)
Adjustment to fair value of warrants issued for purchase of another company			(325)				(325)
Common stock issued for 401(k) match		96	878				974
Other comprehensive income (loss)					4,259		4,259
Balance at Mar. 31, 2019	$ 39	$ 122,052	$ 1,882,613	$ (275,188)	$ (38,210)	$ (20,736)	$ 1,670,570