Schedule II - Condensed Financial Information of Registrant (Parent Company Only) (Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income (loss)	$ (10,629)	$ (1,560)	$ (3,350)	$ 3,986	$ (3,662)	$ 5,048	$ 1,066	$ 4,074	$ (11,553)	$ 6,526	$ 21,863
Adjustments to reconcile net income (loss) to cash provided by (used in) operating activities:
Depreciation and amortization expense									4,715	3,894	3,516
Deferred income tax expense (benefit)									(1,575)	405	(1,030)
Realized loss									205	369	(2,503)
Change in current federal income tax (recoverable)/payable									(3,581)	(2,172)	(2,747)
Change in all other liabilities									3,091	3,586	(1,368)
Change in all other assets									5,487	5,433	(697)
Net cash provided by operating activities									7,199	30,854	52,936
Cash flows from investing activities:
Purchases of property and equipment, net									(2,705)	(4,340)	(3,608)
Purchase of fixed maturity and equity securities									(305,930)	(241,374)	(265,482)
Maturities and redemptions of investment securities									287,187	186,286	169,409
Net cash used in investing activities									(16,772)	(58,233)	(96,289)
Cash flows from financing activities:
Proceeds from exercise of employee stock options									231	466	658
Purchase of treasury shares									(5,308)	(6,117)	(2,532)
Activity under revolving credit facility, net											30,000
Payment of debt issuance costs											(96)
Net cash provided by (used in) financing activities									(5,077)	(7,435)	26,814
Decrease in cash and cash equivalents									(14,650)	(34,814)	(16,539)
Cash and cash equivalents at beginning of year				79,632				114,446	79,632	114,446	130,985
Cash and cash equivalents at end of year	64,982				79,632				64,982	79,632	114,446
Supplemental cash flow information:
Interest paid									4,506	4,287	3,906
Income taxes (recovered) paid									137	3,718	13,800
Parent Company [Member]
Cash flows from operating activities:
Net income (loss)									(11,553)	6,526	21,863
Adjustments to reconcile net income (loss) to cash provided by (used in) operating activities:
Depreciation and amortization expense									367	148	65
Deferred income tax expense (benefit)									(160)	609	(195)
Undistributed share of (earnings) loss of subsidiaries									20,445	1,643	(16,545)
Realized loss									759
Change in current federal income tax (recoverable)/payable									(1,158)	(2,828)	8
Change in all other liabilities									306	1,228	(7,080)
Change in all other assets									632	814	188
Net cash provided by operating activities									9,638	8,140	(1,696)
Cash flows from investing activities:
Purchases of property and equipment, net									(97)	(1,469)	(159)
Purchase of fixed maturity and equity securities									(1,304)
Capital contribution to subsidiaries											(30,000)
Net cash used in investing activities									(1,401)	(1,469)	(30,159)
Cash flows from financing activities:
Proceeds from exercise of employee stock options									231	466	658
Purchase of treasury shares									(5,308)	(6,117)	(2,532)
Activity under revolving credit facility, net											30,000
Payment of debt issuance costs											(96)
Net cash provided by (used in) financing activities									(5,077)	(5,651)	28,030
Decrease in cash and cash equivalents									3,160	1,020	(3,825)
Cash and cash equivalents at beginning of year				$ 9,034				$ 8,014	9,034	8,014	11,839
Cash and cash equivalents at end of year	$ 12,194				$ 9,034				12,194	9,034	8,014
Supplemental cash flow information:
Interest paid									4,506	4,287	3,906
Income taxes (recovered) paid									$ 372	$ 904	$ (1,086)