Consolidated Statements of Stockholders' Equity - Unaudited - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2018		1,200,000	45,074,322
Beginning balance at Dec. 31, 2018	$ 490,336	$ 12	$ 451	$ 454,512	$ 38,371	$ (3,010)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	18,789				18,789
Change in unrealized appreciation on available-for-sale securities	16,521					16,521
Issuance of shares (in shares)			250,968
Issuance of shares	1,717		$ 2	1,715
Issuance of shares from equity-based awards (in shares)			52,351
Issuance of shares from equity-based awards	(236)			(236)
Retired shares (in shares)		(1,200,000)	(10,000)
Retired shares	(30,155)	$ (12)		(30,088)	(55)
Preferred dividends declared	(175)				(175)
Employee receivables from sale of stock	117			4	113
Stock-based compensation	2,245			2,245
Employee stock purchase plan additions	36			36
Ending balance (in shares) at Jun. 30, 2019		0	45,367,641
Ending balance at Jun. 30, 2019	499,195	$ 0	$ 453	430,347	54,816	13,579
Beginning balance (in shares) at Mar. 31, 2019		0	45,202,370
Beginning balance at Mar. 31, 2019	480,514	$ 0	$ 452	428,412	45,293	6,357
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	9,439				9,439
Change in unrealized appreciation on available-for-sale securities	7,222					7,222
Issuance of shares (in shares)			149,765
Issuance of shares	890		$ 1	889
Issuance of shares from equity-based awards (in shares)			15,506
Issuance of shares from equity-based awards	(102)			(102)
Employee receivables from sale of stock	86			2	84
Stock-based compensation	1,147			1,147
Employee stock purchase plan additions	(1)			(1)
Ending balance (in shares) at Jun. 30, 2019		0	45,367,641
Ending balance at Jun. 30, 2019	499,195	$ 0	$ 453	430,347	54,816	13,579
Beginning balance (in shares) at Dec. 31, 2019		0	51,969,203
Beginning balance at Dec. 31, 2019	601,644	$ 0	$ 520	519,870	64,803	16,451
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(3,499)				(3,499)
Change in unrealized appreciation on available-for-sale securities	8,643					8,643
Issuance of shares from equity-based awards (in shares)			198,370
Issuance of shares from equity-based awards	(753)		$ 1	(754)
Employee receivables from sale of stock	41			1	40
Stock-based compensation	2,016			2,016
Ending balance (in shares) at Jun. 30, 2020		0	52,167,573
Ending balance at Jun. 30, 2020	608,092	$ 0	$ 521	521,133	61,344	25,094
Beginning balance (in shares) at Mar. 31, 2020		0	52,098,062
Beginning balance at Mar. 31, 2020	611,946	$ 0	$ 521	520,134	68,689	22,602
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(7,356)				(7,356)
Change in unrealized appreciation on available-for-sale securities	2,492					2,492
Issuance of shares from equity-based awards (in shares)			69,511
Issuance of shares from equity-based awards	(83)			(83)
Employee receivables from sale of stock	11				11
Stock-based compensation	1,082			1,082
Ending balance (in shares) at Jun. 30, 2020		0	52,167,573
Ending balance at Jun. 30, 2020	$ 608,092	$ 0	$ 521	$ 521,133	$ 61,344	$ 25,094