Fair Value Measurements (Available for Sale) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	$ 154,679	$ 143,084
Unrealized Gains	221	1,523
Unrealized Losses	(7,992)	(1,396)
Fair Value	146,908	143,211
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	116,874	83,656
Less than 12 Months, Unrealized Losses	(6,428)	(1,308)
12 Months or Greater, Fair Value	17,541	2,652
12 Months or Greater, Unrealized Losses	(1,564)	(88)
Total, Fair Value	134,415	86,308
Total, Unrealized Losses	(7,992)	(1,396)
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract]
Amortized Cost, Due within one year	22,628
Fair Value, Due within one year	22,529
Amortized Cost, Due after one year through five years	121,155
Fair Value, Due after one year through five years	114,512
Amortized Cost, Due after five years	10,896
Fair Value, Due after five years	9,867
Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	89,263	84,011
Unrealized Gains	24	999
Unrealized Losses	(4,789)	(655)
Fair Value	84,498	84,355
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	61,268	37,170
Less than 12 Months, Unrealized Losses	(3,312)	(572)
12 Months or Greater, Fair Value	15,194	1,938
12 Months or Greater, Unrealized Losses	(1,477)	(83)
Total, Fair Value	76,462	39,108
Total, Unrealized Losses	(4,789)	(655)
Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	65,416	59,073
Unrealized Gains	197	524
Unrealized Losses	(3,203)	(741)
Fair Value	62,410	58,856
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	55,606	46,486
Less than 12 Months, Unrealized Losses	(3,116)	(736)
12 Months or Greater, Fair Value	2,347	714
12 Months or Greater, Unrealized Losses	(87)	(5)
Total, Fair Value	57,953	47,200
Total, Unrealized Losses	(3,203)	(741)
Corporate debt securities | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	50,971	46,649
Unrealized Gains	22	438
Unrealized Losses	(2,758)	(438)
Fair Value	48,235	46,649
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	32,447	28,639
Less than 12 Months, Unrealized Losses	(1,911)	(434)
12 Months or Greater, Fair Value	9,058	207
12 Months or Greater, Unrealized Losses	(847)	(4)
Total, Fair Value	41,505	28,846
Total, Unrealized Losses	(2,758)	(438)
Corporate debt securities | Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	64,601	58,261
Unrealized Gains	8	72
Unrealized Losses	(3,203)	(741)
Fair Value	61,406	57,592
U.S. government agency securities | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	28,346	28,316
Unrealized Gains	2	459
Unrealized Losses	(1,063)	(133)
Fair Value	27,285	28,642
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	21,624	5,382
Less than 12 Months, Unrealized Losses	(666)	(97)
12 Months or Greater, Fair Value	4,462	824
12 Months or Greater, Unrealized Losses	(397)	(36)
Total, Fair Value	26,086	6,206
Total, Unrealized Losses	(1,063)	(133)
Municipal bonds | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	9,380	8,475
Unrealized Gains	0	100
Unrealized Losses	(926)	(78)
Fair Value	8,454	8,497
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	6,843	2,714
Less than 12 Months, Unrealized Losses	(709)	(35)
12 Months or Greater, Fair Value	1,559	907
12 Months or Greater, Unrealized Losses	(217)	(43)
Total, Fair Value	8,402	3,621
Total, Unrealized Losses	(926)	(78)
Municipal bonds | Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	815	812
Unrealized Gains	189	452
Unrealized Losses	0	0
Fair Value	1,004	1,264
Corporate certificates of deposit | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	566	571
Unrealized Gains	0	2
Unrealized Losses	(42)	(6)
Fair Value	524	567
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	354	435
Less than 12 Months, Unrealized Losses	(26)	(6)
12 Months or Greater, Fair Value	115	0
12 Months or Greater, Unrealized Losses	(16)	0
Total, Fair Value	469	435
Total, Unrealized Losses	$ (42)	$ (6)