CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]	Total
Balances at Dec. 31, 2017		$ 2	$ 172,325	$ (6,122)	$ 397,640	$ 563,845
Balances, Shares at Dec. 31, 2017		20,391,000
Net income					17,138	17,138
Preferred stock dividends					(21)	(21)
Foreign currency translation adjustment				310		310
Issuance of common and preferred stock, net of offering costs	$ 40,000		956			40,956
Issuance of common and preferred stock, net of offering costs, Shares	1,600,000	100,000
Stock-based compensation			592			592
Stock-based compensation, Shares		2,000
Balances at Mar. 31, 2018	$ 40,000	$ 2	173,873	(5,812)	414,757	622,820
Balances, Shares at Mar. 31, 2018	1,600,000	20,493,000
Balances at Dec. 31, 2017		$ 2	172,325	(6,122)	397,640	563,845
Balances, Shares at Dec. 31, 2017		20,391,000
Net income						59,189
Preferred stock dividends						(2,917)
Foreign currency translation adjustment						(257)
Balances at Sep. 30, 2018	$ 103,865	$ 2	145,069	(6,379)	453,912	696,469
Balances, Shares at Sep. 30, 2018	4,155,000	19,306,000
Balances at Mar. 31, 2018	$ 40,000	$ 2	173,873	(5,812)	414,757	622,820
Balances, Shares at Mar. 31, 2018	1,600,000	20,493,000
Net income					20,297	20,297
Preferred stock dividends					(1,148)	(1,148)
Foreign currency translation adjustment				(548)		(548)
Issuance of common and preferred stock, net of offering costs	$ 14,990					14,620
Issuance of common and preferred stock, net of offering costs			(370)
Issuance of common and preferred stock, net of offering costs, Shares	600,000
Repurchase of common stock			(27,946)			(27,946)
Repurchase of common stock, Shares		(1,225,000)
Stock-based compensation			653			653
Stock-based compensation, Shares		38,000
Balances at Jun. 30, 2018	$ 54,990	$ 2	146,210	(6,360)	433,906	628,748
Balances, Shares at Jun. 30, 2018	2,200,000	19,306,000
Net income					21,754	21,754
Preferred stock dividends					(1,748)	(1,748)
Foreign currency translation adjustment				(19)		(19)
Issuance of common and preferred stock, net of offering costs	$ 48,875					46,982
Issuance of common and preferred stock, net of offering costs			(1,893)
Issuance of common and preferred stock, net of offering costs, Shares	1,955,000
Stock-based compensation			752			752
Balances at Sep. 30, 2018	$ 103,865	$ 2	145,069	(6,379)	453,912	696,469
Balances, Shares at Sep. 30, 2018	4,155,000	19,306,000
Balances at Dec. 31, 2018	$ 103,865	$ 2	132,666	(6,513)	471,112	701,132
Balances, Shares at Dec. 31, 2018	4,155,000	18,764,000
Net income					18,574	18,574
Preferred stock dividends					(2,207)	(2,207)
Foreign currency translation adjustment				(81)		(81)
Repurchase of common stock			(13,946)			(13,946)
Repurchase of common stock, Shares		(595,000)
Stock-based compensation			837			837
Stock-based compensation, Shares		39,000
Balances at Mar. 31, 2019	$ 103,865	$ 2	119,557	(6,594)	487,479	704,309
Balances, Shares at Mar. 31, 2019	4,155,000	18,208,000
Balances at Dec. 31, 2018	$ 103,865	$ 2	132,666	(6,513)	471,112	701,132
Balances, Shares at Dec. 31, 2018	4,155,000	18,764,000
Net income						23,162
Preferred stock dividends						(6,621)
Foreign currency translation adjustment						(332)
Repurchase of common stock						$ (34,100)
Repurchase of common stock, Shares						(1,500,000)
Balances at Sep. 30, 2019	$ 103,865	$ 2	101,317	(6,845)	487,653	$ 685,992
Balances, Shares at Sep. 30, 2019	4,155,000	17,426,000
Balances at Mar. 31, 2019	$ 103,865	$ 2	119,557	(6,594)	487,479	704,309
Balances, Shares at Mar. 31, 2019	4,155,000	18,208,000
Net income					9,335	9,335
Preferred stock dividends					(2,207)	(2,207)
Foreign currency translation adjustment				5		5
Repurchase of common stock		$ (863)	(20,172)			(20,172)
Stock-based compensation			916			916
Stock-based compensation, Shares		75,000
Balances at Jun. 30, 2019	$ 103,865	$ 2	100,301	(6,589)	494,607	692,186
Balances, Shares at Jun. 30, 2019	4,155,000	17,420,000
Net income					(4,747)	(4,747)
Preferred stock dividends					(2,207)	(2,207)
Foreign currency translation adjustment				(256)		$ (256)
Repurchase of common stock, Shares						0
Stock-based compensation			1,016			$ 1,016
Stock-based compensation, Shares		6,000
Balances at Sep. 30, 2019	$ 103,865	$ 2	$ 101,317	$ (6,845)	$ 487,653	$ 685,992
Balances, Shares at Sep. 30, 2019	4,155,000	17,426,000