Fair Value Measurements (Available for Sale) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	$ 223,300	$ 222,134
Unrealized Gains	741	1,272
Unrealized Losses	(5,928)	(6,158)
Fair Value	218,113	217,248
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	50,289	17,748
Less than 12 Months, Unrealized Losses	(272)	(64)
12 Months or Greater, Fair Value	105,580	120,731
12 Months or Greater, Unrealized Losses	(5,656)	(6,094)
Total, Fair Value	155,869	138,479
Total, Unrealized Losses	(5,928)	(6,158)
Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Fair Value [Abstract]
Amortized Cost, Due within one year	38,792
Fair Value, Due within one year	38,009
Amortized Cost, Due after one year through five years	174,478
Fair Value, Due after one year through five years	171,095
Amortized Cost, Due after five years	10,030
Fair Value, Due after five years	9,009
Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	134,342	133,710
Unrealized Gains	403	785
Unrealized Losses	(4,246)	(4,208)
Fair Value	130,499	130,287
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	25,575	6,350
Less than 12 Months, Unrealized Losses	(147)	(9)
12 Months or Greater, Fair Value	59,655	71,005
12 Months or Greater, Unrealized Losses	(4,099)	(4,199)
Total, Fair Value	85,230	77,355
Total, Unrealized Losses	(4,246)	(4,208)
Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	88,958	88,424
Unrealized Gains	338	487
Unrealized Losses	(1,682)	(1,950)
Fair Value	87,614	86,961
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	24,714	11,398
Less than 12 Months, Unrealized Losses	(125)	(55)
12 Months or Greater, Fair Value	45,925	49,726
12 Months or Greater, Unrealized Losses	(1,557)	(1,895)
Total, Fair Value	70,639	61,124
Total, Unrealized Losses	(1,682)	(1,950)
Corporate debt securities | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	101,568	95,903
Unrealized Gains	395	762
Unrealized Losses	(2,257)	(2,202)
Fair Value	99,706	94,463
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	22,242	4,971
Less than 12 Months, Unrealized Losses	(123)	(3)
12 Months or Greater, Fair Value	37,507	40,649
12 Months or Greater, Unrealized Losses	(2,134)	(2,199)
Total, Fair Value	59,749	45,620
Total, Unrealized Losses	(2,257)	(2,202)
Corporate debt securities | Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	88,134	87,601
Unrealized Gains	105	246
Unrealized Losses	(1,682)	(1,950)
Fair Value	86,557	85,897
U.S. government agency securities | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	24,380	29,082
Unrealized Gains	4	18
Unrealized Losses	(1,050)	(1,054)
Fair Value	23,334	28,046
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	3,333	1,280
Less than 12 Months, Unrealized Losses	(24)	(4)
12 Months or Greater, Fair Value	14,869	22,858
12 Months or Greater, Unrealized Losses	(1,026)	(1,050)
Total, Fair Value	18,202	24,138
Total, Unrealized Losses	(1,050)	(1,054)
Municipal bonds | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	7,899	8,227
Unrealized Gains	4	5
Unrealized Losses	(908)	(914)
Fair Value	6,995	7,318
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	0	99
Less than 12 Months, Unrealized Losses	0	(2)
12 Months or Greater, Fair Value	6,814	7,038
12 Months or Greater, Unrealized Losses	(908)	(912)
Total, Fair Value	6,814	7,137
Total, Unrealized Losses	(908)	(914)
Municipal bonds | Investments in lieu of retention:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	824	823
Unrealized Gains	233	241
Unrealized Losses	0	0
Fair Value	1,057	1,064
Corporate certificates of deposit | Restricted investments:
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	495	498
Unrealized Gains	0	0
Unrealized Losses	(31)	(38)
Fair Value	464	460
Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or Greater, Fair Value	465	460
12 Months or Greater, Unrealized Losses	(31)	(38)
Total, Fair Value	465	460
Total, Unrealized Losses	$ (31)	$ (38)