Reserves for Losses and Loss Adjustment Expenses (Incurred and Paid Claims Development - Runoff) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) claim	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development	$ 58,288	$ 60,900
Incurred claims and claim adjustment expenses related to current year	332,863	301,265
Total incurred	412,851	362,165
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years	185,407	192,335
Paid claims and allocated claim adjustment expenses related to current year	113,312	127,610
Total paid	320,419	319,945
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	440,183	347,751	$ 305,531
Loss Adjustment Expenses Recognized In 2011 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years										$ 2,897
Runoff [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total incurred	40,568
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Total paid	40,062
All outstanding liabilities before 2011, net of reinsurance	1,720
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	2,226
Runoff [Member] | Loss Adjustment Expenses Recognized In 2011 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development		6,637	6,659	$ 6,741	$ 6,678	$ 6,185	$ 7,547	$ 9,433	$ 9,949	$ 10,861
Incurred claims and claim adjustment expenses related to current year	4,666
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 106
Cumulative number of reported claims | claim	965
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years	$ 5,630	5,357	5,483	5,427	5,227	4,838	4,968	5,208	4,308
Runoff [Member] | Loss Adjustment Expenses Recognized In 2012 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development		2,752	2,752	2,636	2,821	3,358	3,597	4,469	4,804
Incurred claims and claim adjustment expenses related to current year	2,773
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 91
Cumulative number of reported claims | claim	714
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years	$ 2,675	2,675	2,602	2,600	2,583	2,594	2,411	2,107	$ 1,181
Runoff [Member] | Loss Adjustment Expenses Recognized In 2013 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development		9,486	9,472	9,257	9,257	9,713	10,143	9,069
Incurred claims and claim adjustment expenses related to current year	9,483
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 228
Cumulative number of reported claims | claim	1,337
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years	$ 9,050	9,010	8,961	8,809	8,350	7,882	6,825	$ 3,737
Runoff [Member] | Loss Adjustment Expenses Recognized In 2014 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development		10,463	10,452	10,076	9,762	9,338	9,208
Incurred claims and claim adjustment expenses related to current year	10,292
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 719
Cumulative number of reported claims | claim	1,027
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years	$ 9,487	9,323	9,210	9,004	7,970	5,972	$ 2,933
Runoff [Member] | Loss Adjustment Expenses Recognized in 2015 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development		8,420	8,892	8,624	7,277	8,605
Incurred claims and claim adjustment expenses related to current year	8,526
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 186
Cumulative number of reported claims | claim	822
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years	$ 8,512	8,495	8,049	7,328	5,744	$ 2,528
Runoff [Member] | Loss Adjustment Expenses Recognized in 2016 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development		4,416	4,365	4,733	3,553
Incurred claims and claim adjustment expenses related to current year	$ 4,425
Cumulative number of reported claims | claim	462
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years	$ 4,425	4,418	3,743	2,550	$ 1,732
Runoff [Member] | Loss Adjustment Expenses Recognized in 2017 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development		415	465	450
Incurred claims and claim adjustment expenses related to current year	403
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 60
Cumulative number of reported claims | claim	66
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years	$ 282	$ 203	$ 171	$ 111