Fair Value Measurements (Available for Sale) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	$ 180,748	$ 169,876
Unrealized Gains	202	180
Unrealized Losses	(9,360)	(10,272)
Fair Value	171,590	159,784
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	59,065	88,007
Less than 12 Months, Unrealized Losses	(621)	(3,199)
12 Months or Greater, Fair Value	110,502	67,173
12 Months or Greater, Unrealized Losses	(8,739)	(7,073)
Total, Fair Value	169,567	155,180
Total, Unrealized Losses	(9,360)	(10,272)
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract]
Amortized Cost, Due within one year	28,601
Fair Value, Due within one year	28,095
Amortized Cost, Due after one year through five years	141,769
Fair Value, Due after one year through five years	134,459
Amortized Cost, Due after five years	10,378
Fair Value, Due after five years	9,036
Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	103,317	98,090
Unrealized Gains	0	14
Unrealized Losses	(6,024)	(6,548)
Fair Value	97,293	91,556
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	32,366	53,454
Less than 12 Months, Unrealized Losses	(322)	(2,356)
12 Months or Greater, Fair Value	63,926	34,782
12 Months or Greater, Unrealized Losses	(5,702)	(4,192)
Total, Fair Value	96,292	88,236
Total, Unrealized Losses	(6,024)	(6,548)
Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	77,431	71,786
Unrealized Gains	202	166
Unrealized Losses	(3,336)	(3,724)
Fair Value	74,297	68,228
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	26,699	34,553
Less than 12 Months, Unrealized Losses	(299)	(843)
12 Months or Greater, Fair Value	46,576	32,391
12 Months or Greater, Unrealized Losses	(3,037)	(2,881)
Total, Fair Value	73,275	66,944
Total, Unrealized Losses	(3,336)	(3,724)
Corporate debt securities | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	64,151	53,452
Unrealized Gains	0	1
Unrealized Losses	(3,350)	(3,550)
Fair Value	60,801	49,903
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	23,921	23,559
Less than 12 Months, Unrealized Losses	(227)	(733)
12 Months or Greater, Fair Value	35,880	25,842
12 Months or Greater, Unrealized Losses	(3,123)	(2,817)
Total, Fair Value	59,801	49,401
Total, Unrealized Losses	(3,350)	(3,550)
Corporate debt securities | Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	76,611	70,968
Unrealized Gains	0	1
Unrealized Losses	(3,336)	(3,724)
Fair Value	73,275	67,245
U.S. government agency securities | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	30,126	34,920
Unrealized Gains	0	13
Unrealized Losses	(1,534)	(1,688)
Fair Value	28,592	33,245
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	8,097	24,834
Less than 12 Months, Unrealized Losses	(90)	(939)
12 Months or Greater, Fair Value	20,494	5,593
12 Months or Greater, Unrealized Losses	(1,444)	(749)
Total, Fair Value	28,591	30,427
Total, Unrealized Losses	(1,534)	(1,688)
Municipal bonds | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	8,538	9,211
Unrealized Gains	0	0
Unrealized Losses	(1,087)	(1,257)
Fair Value	7,451	7,954
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	348	4,998
Less than 12 Months, Unrealized Losses	(5)	(672)
12 Months or Greater, Fair Value	7,103	2,956
12 Months or Greater, Unrealized Losses	(1,082)	(585)
Total, Fair Value	7,451	7,954
Total, Unrealized Losses	(1,087)	(1,257)
Municipal bonds | Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	820	818
Unrealized Gains	202	165
Unrealized Losses	0	0
Fair Value	1,022	983
Corporate certificates of deposit | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	502	507
Unrealized Gains	0	0
Unrealized Losses	(53)	(53)
Fair Value	449	454
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	0	63
Less than 12 Months, Unrealized Losses	0	(12)
12 Months or Greater, Fair Value	449	391
12 Months or Greater, Unrealized Losses	(53)	(41)
Total, Fair Value	449	454
Total, Unrealized Losses	$ (53)	$ (53)