Significant Accounting Policies - Narrative (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($) payment	Dec. 31, 2023 USD ($) reportingUnit category payment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Significant Accounting Policies Line Items [Line Items]
Maximum maturity duration for short term investment grouping		12 months
Number of payments missed for insured loans | payment	2	2
Number of reporting units | reportingUnit		1
Goodwill	$ 0	$ 0	$ 9,802
Impairment of goodwill	$ 10,000	9,802	0	$ 0
Depreciation and amortization expense		$ 15,000	15,000	$ 16,000
Minimum
Significant Accounting Policies Line Items [Line Items]
Number of payments missed for insured loans | payment	2	2
Useful life	3 years	3 years
Maximum
Significant Accounting Policies Line Items [Line Items]
Useful life	7 years	7 years
Mortgage Insurance
Significant Accounting Policies Line Items [Line Items]
Number of mortgage insurance product categories | category		2
Premium receivable for deferred monthly premiums	$ 36,000	$ 36,000	32,000
Contractual deferred monthly premiums	$ 81,000	$ 81,000	$ 77,000