Fair Value Measurements (Available for Sale) (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	$ 163,946	$ 169,876
Unrealized Gains	306	180
Unrealized Losses	(8,713)	(10,272)
Fair Value	155,539	159,784
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	39,040	88,007
Less than 12 Months, Unrealized Losses	(527)	(3,199)
12 Months or Greater, Fair Value	100,779	67,173
12 Months or Greater, Unrealized Losses	(8,186)	(7,073)
Total, Fair Value	139,819	155,180
Total, Unrealized Losses	(8,713)	(10,272)
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract]
Amortized Cost, Due within one year	25,973
Fair Value, Due within one year	25,531
Amortized Cost, Due after one year through five years	127,355
Fair Value, Due after one year through five years	120,639
Amortized Cost, Due after five years	10,618
Fair Value, Due after five years	9,369
Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	93,669	98,090
Unrealized Gains	65	14
Unrealized Losses	(5,494)	(6,548)
Fair Value	88,240	91,556
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	25,975	53,454
Less than 12 Months, Unrealized Losses	(381)	(2,356)
12 Months or Greater, Fair Value	54,429	34,782
12 Months or Greater, Unrealized Losses	(5,113)	(4,192)
Total, Fair Value	80,404	88,236
Total, Unrealized Losses	(5,494)	(6,548)
Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	70,277	71,786
Unrealized Gains	241	166
Unrealized Losses	(3,219)	(3,724)
Fair Value	67,299	68,228
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	13,065	34,553
Less than 12 Months, Unrealized Losses	(146)	(843)
12 Months or Greater, Fair Value	46,350	32,391
12 Months or Greater, Unrealized Losses	(3,073)	(2,881)
Total, Fair Value	59,415	66,944
Total, Unrealized Losses	(3,219)	(3,724)
Corporate debt securities | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	52,027	53,452
Unrealized Gains	22	1
Unrealized Losses	(3,045)	(3,550)
Fair Value	49,004	49,903
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	11,456	23,559
Less than 12 Months, Unrealized Losses	(204)	(733)
12 Months or Greater, Fair Value	32,499	25,842
12 Months or Greater, Unrealized Losses	(2,841)	(2,817)
Total, Fair Value	43,955	49,401
Total, Unrealized Losses	(3,045)	(3,550)
Corporate debt securities | Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	69,458	70,968
Unrealized Gains	31	1
Unrealized Losses	(3,219)	(3,724)
Fair Value	66,270	67,245
U.S. government agency securities | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	32,099	34,920
Unrealized Gains	43	13
Unrealized Losses	(1,379)	(1,688)
Fair Value	30,763	33,245
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	13,782	24,834
Less than 12 Months, Unrealized Losses	(154)	(939)
12 Months or Greater, Fair Value	14,194	5,593
12 Months or Greater, Unrealized Losses	(1,225)	(749)
Total, Fair Value	27,976	30,427
Total, Unrealized Losses	(1,379)	(1,688)
Municipal bonds | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	9,039	9,211
Unrealized Gains	0	0
Unrealized Losses	(1,017)	(1,257)
Fair Value	8,022	7,954
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	737	4,998
Less than 12 Months, Unrealized Losses	(23)	(672)
12 Months or Greater, Fair Value	7,285	2,956
12 Months or Greater, Unrealized Losses	(994)	(585)
Total, Fair Value	8,022	7,954
Total, Unrealized Losses	(1,017)	(1,257)
Municipal bonds | Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	819	818
Unrealized Gains	210	165
Unrealized Losses	0	0
Fair Value	1,029	983
Corporate certificates of deposit | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	504	507
Unrealized Gains	0	0
Unrealized Losses	(53)	(53)
Fair Value	451	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	451	391
12 Months or Greater, Unrealized Losses	(53)	(41)
Total, Fair Value	451	454
Total, Unrealized Losses	$ (53)	$ (53)