Reserves for Losses and Loss Adjustment Expenses (Incurred and Paid Claims Development - Personal Segment) (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
Personal Segment [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development	9,123	36
Total incurred	438,481
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to current year	50
Total paid	419,934
Liabilities for unpaid claims and claim adjustment expenses, net of reinsurance	18,597
Personal Segment [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		87,198	87,199	$ 86,853	$ 86,948	$ 86,804	$ 86,757	$ 87,810	$ 77,652	75,746
Incurred claims and claim adjustment expenses related to current year	$ 87,087
Cumulative number of reported claims	31,615
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years		87,045	86,989	86,660	86,593	86,217	85,533	83,497	67,939	$ 46,416
Paid claims and allocated claim adjustment expenses related to current year	$ 87,042
Personal Segment [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		72,100	72,076	72,037	72,042	71,513	70,552	73,795	58,604
Incurred claims and claim adjustment expenses related to current year	$ 72,123
Cumulative number of reported claims | claim	23,940
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years		72,124	72,094	72,055	71,995	70,807	68,849	64,278	$ 37,860
Paid claims and allocated claim adjustment expenses related to current year	$ 72,138
Personal Segment [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		60,310	60,328	60,379	60,211	60,100	59,132	55,706
Incurred claims and claim adjustment expenses related to current year	$ 60,286
Cumulative number of reported claims | claim	23,472
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years		60,279	60,297	60,277	59,775	58,047	54,514	$ 45,901
Paid claims and allocated claim adjustment expenses related to current year	$ 60,279
Personal Segment [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		6,518	6,504	6,699	6,243	5,340	5,452
Incurred claims and claim adjustment expenses related to current year	$ 6,578
Cumulative number of reported claims | claim	19,293
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years		6,580	6,566	6,428	5,631	4,418	$ 2,515
Paid claims and allocated claim adjustment expenses related to current year	$ 6,583
Personal Segment [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		25,102	25,136	25,307	25,682	23,104
Incurred claims and claim adjustment expenses related to current year	$ 25,185
Cumulative number of reported claims | claim	23,376
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years		25,098	25,243	24,262	22,281	$ 11,570
Paid claims and allocated claim adjustment expenses related to current year	$ 25,169
Personal Segment [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		32,803	32,728	32,893	32,260
Incurred claims and claim adjustment expenses related to current year	$ 33,042
Cumulative number of reported claims | claim	23,757
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years		32,777	32,260	30,646	$ 21,669
Paid claims and allocated claim adjustment expenses related to current year	$ 32,991
Personal Segment [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		21,926	21,968	23,342
Incurred claims and claim adjustment expenses related to current year	$ 22,547
Cumulative number of reported claims | claim	16,810
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years		21,972	21,061	$ 15,776
Paid claims and allocated claim adjustment expenses related to current year	$ 22,488
Personal Segment [Member] | Loss Adjustment Expenses Recognized In 2018 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development		18,353	18,334
Incurred claims and claim adjustment expenses related to current year	19,972
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 30
Cumulative number of reported claims | claim	15,321
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years		18,009	$ 11,137
Paid claims and allocated claim adjustment expenses related to current year	$ 19,628
Personal Segment [Member] | Loss Adjustment Expenses Recognized In 2019 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Total unfavorable (favorable) net prior year development		56,009
Incurred claims and claim adjustment expenses related to current year	63,722
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ (1,025)
Cumulative number of reported claims | claim	25,627
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to prior years		$ 41,524
Paid claims and allocated claim adjustment expenses related to current year	$ 60,870
Personal Segment [Member] | Loss Adjustment Expenses Recognized In 2020 [Member]
Liability For Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract]
Incurred claims and claim adjustment expenses related to current year	47,938
Total of incurred-but-not-reported liabilities plus expected development on reported claims	$ 5,351
Cumulative number of reported claims | claim	17,510
Liability For Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract]
Paid claims and allocated claim adjustment expenses related to current year	$ 32,746