Fair Value of Financial Instruments - Quantitative Information About Level 3 Fair Value Measurements (Details) $ in Thousands	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities	$ 1,591,169	$ 1,551,336
Asset-backed securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities	4,325	4,253
Recurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities	1,591,348	1,551,339
Recurring \| Asset-backed securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities	4,325	4,253
Recurring \| Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities	6,264	6,476
Recurring \| Level 3 \| Corporate bonds
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities	$ 5,413
Recurring \| Level 3 \| Corporate bonds \| Discounted cash flow \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities, range of weighted average significant unobservable inputs	0.035
Recurring \| Level 3 \| Corporate bonds \| Discounted cash flow \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities, range of weighted average significant unobservable inputs	0.075
Recurring \| Level 3 \| Asset-backed securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities	$ 851	$ 801
Recurring \| Level 3 \| Asset-backed securities \| Discounted cash flow \| Minimum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities, range of weighted average significant unobservable inputs	0.04
Recurring \| Level 3 \| Asset-backed securities \| Discounted cash flow \| Maximum
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Available-for-sale securities, range of weighted average significant unobservable inputs	0.06

Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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Value of input used to measure investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI https://asc.fasb.org/extlink&oid=126976982&loc=d3e19207-110258

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