Fair Value of Financial Instruments - Rollforward of Balance Sheet Amounts Within Level 3 Valuation Hierarchy (Details) - USD ($)	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Assets measured on recurring basis, unobservable input reconciliation, calculation [Roll Forward]
Transfers out of Level 3	$ 0
Available-for-sale Securities
Assets measured on recurring basis, unobservable input reconciliation, calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	1
Recurring | Other investments
Assets measured on recurring basis, unobservable input reconciliation, calculation [Roll Forward]
Fair value, beginning of period	157,140,000	$ 130,982,000
Total realized gains (losses) included in income	(714,000)	2,360,000
Changes in unrealized gains/losses included in other comprehensive income (loss)	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0	0
Purchases	7,467,000	9,202,000
Issuances	0	0
Settlements	(1,658,000)	(1,534,000)
Transfers out of Level 3	0	0
Fair value, end of period	162,235,000	141,010,000
Total realized gains (losses) included in income	(714,000)	2,360,000
Recurring | Available-for-sale Securities
Assets measured on recurring basis, unobservable input reconciliation, calculation [Roll Forward]
Fair value, beginning of period	479,000	629,000
Total realized gains (losses) included in income	13,000	1,000
Changes in unrealized gains/losses included in other comprehensive income (loss)	16,000	8,000
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	12,841,000	0
Purchases	0	0
Issuances	0	0
Settlements	(165,000)	(159,000)
Transfers out of Level 3	0	0
Fair value, end of period	13,184,000	479,000
Total realized gains (losses) included in income	13,000	$ 1,000
Recurring | Servicing Contracts
Assets measured on recurring basis, unobservable input reconciliation, calculation [Roll Forward]
Fair value, beginning of period	0
Total realized gains (losses) included in income	11,812,000
Changes in unrealized gains/losses included in other comprehensive income (loss)	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0
Purchases	0
Issuances	0
Settlements	0
Transfers out of Level 3	0
Fair value, end of period	11,812,000
Total realized gains (losses) included in income	$ 11,812,000