Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Retained Earnings [Member]
Beginning balance at Dec. 31, 2017	$ 88,834	$ 73	$ 12,311	$ (1,430)	$ 77,880
Beginning balance, shares at Dec. 31, 2017		7,301
Common stock issued on exercise of options and vesting of restricted stock units and performance awards	53		53
Common stock issued on exercise of options and vesting of restricted stock units and performance awards, shares		7
Common stock repurchased on vesting of restricted stock units and performance awards	(76)		(76)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(1)
Share-based compensation expense	1,542		1,542
Cash dividends on common stock	(1,826)				(1,826)
Unrealized gains (losses) on investments, net of tax	(3,964)			(3,964)
Net income (loss)	(9,123)				(9,123)
Ending balance at Mar. 31, 2018	75,440	$ 73	13,830	(5,394)	66,931
Beginning balance, shares at Mar. 31, 2018		7,307
Beginning balance at Dec. 31, 2017	88,834	$ 73	12,311	(1,430)	77,880
Beginning balance, shares at Dec. 31, 2017		7,301
Unrealized gains (losses) on investments, net of tax	(4,939)
Net income (loss)	2,117
Ending balance at Jun. 30, 2018	84,875	$ 73	14,827	(6,369)	76,344
Beginning balance, shares at Jun. 30, 2018		7,311
Beginning balance at Mar. 31, 2018	75,440	$ 73	13,830	(5,394)	66,931
Beginning balance, shares at Mar. 31, 2018		7,307
Common stock issued on exercise of options and vesting of restricted stock units and performance awards	48		48
Common stock issued on exercise of options and vesting of restricted stock units and performance awards, shares		5
Common stock repurchased on vesting of restricted stock units and performance awards	(92)		(92)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(1)
Share-based compensation expense	1,041		1,041
Cash dividends on common stock	(1,827)				(1,827)
Unrealized gains (losses) on investments, net of tax	(975)			(975)
Net income (loss)	11,240				11,240
Ending balance at Jun. 30, 2018	84,875	$ 73	14,827	(6,369)	76,344
Beginning balance, shares at Jun. 30, 2018		7,311
Beginning balance at Dec. 31, 2018	119,037	$ 74	15,437	(5,068)	108,594
Beginning balance, shares at Dec. 31, 2018		7,395
Common stock issued on exercise of options and vesting of restricted stock units and performance awards	122		122
Common stock issued on exercise of options and vesting of restricted stock units and performance awards, shares		17
Common stock repurchased on vesting of restricted stock units and performance awards	(178)		(178)
Common stock repurchased on vesting of restricted stock units and performance awards, shares		(2)
Share-based compensation expense	1,387		1,387
Cash dividends on common stock	(1,852)				(1,852)
Unrealized gains (losses) on investments, net of tax	3,657			3,657
Net income (loss)	(2,300)				(2,300)
Ending balance at Mar. 31, 2019	119,873	$ 74	16,768	(1,411)	104,442
Beginning balance, shares at Mar. 31, 2019		7,410
Beginning balance at Dec. 31, 2018	119,037	$ 74	15,437	(5,068)	108,594
Beginning balance, shares at Dec. 31, 2018		7,395
Unrealized gains (losses) on investments, net of tax	6,700
Net income (loss)	11,607
Ending balance at Jun. 30, 2019	137,467	$ 74	19,265	1,632	116,496
Beginning balance, shares at Jun. 30, 2019		7,414
Beginning balance at Mar. 31, 2019	119,873	$ 74	16,768	(1,411)	104,442
Beginning balance, shares at Mar. 31, 2019		7,410
Common stock issued on exercise of options and vesting of restricted stock units and performance awards	56		56
Common stock issued on exercise of options and vesting of restricted stock units and performance awards, shares		4
Share-based compensation expense	2,441		2,441
Cash dividends on common stock	(1,853)				(1,853)
Unrealized gains (losses) on investments, net of tax	3,043			3,043
Net income (loss)	13,907				13,907
Ending balance at Jun. 30, 2019	$ 137,467	$ 74	$ 19,265	$ 1,632	$ 116,496
Beginning balance, shares at Jun. 30, 2019		7,414