Investments - Schedule of Available for Sale Investment Purchases, Proceeds and Gains & Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Purchases of AFS securities	$ 142,420	$ 49,285	$ 285,151	$ 111,280
Proceeds from maturities, calls and prepayments of AFS securities	16,616	21,643	51,245	65,492
Gross proceeds from sales of AFS securities	29,713	2,873	62,902	15,249
Gross realized gains	303	115	625	274
Gross realized (losses)	(7)	0	(9)	(63)
Total net realized gains (losses) from investment sales and redemptions	$ 296	$ 115	$ 616	$ 211

Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of cash outflow to acquire investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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