Fair Value Measurements - Fair Value Measurement on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets
Fair Value	$ 802,163	$ 952,312
U.S. government and agency securities
Assets
Fair Value	45,660	105,223
Municipal securities
Assets
Fair Value	209,968	133,014
Residential mortgage-backed securities
Assets
Fair Value	201,872	339,608
Commercial mortgage-backed securities
Assets
Fair Value	303,746	327,095
Other asset-backed securities
Assets
Fair Value	11,096	24,194
Other Security Investments
Assets
Fair Value	29,821	23,178
Recurring
Assets
Fair Value	802,163	952,312
Equity security	131	148
Recurring \| U.S. government and agency securities
Assets
Fair Value	45,660	105,223
Recurring \| Municipal securities
Assets
Fair Value	209,968	133,014
Recurring \| Residential mortgage-backed securities
Assets
Fair Value	201,872	339,608
Recurring \| Commercial mortgage-backed securities
Assets
Fair Value	303,746	327,095
Recurring \| Other asset-backed securities
Assets
Fair Value	11,096	24,194
Recurring \| Other Security Investments
Assets
Fair Value	29,821	23,178
Recurring \| Interest Rate Swap
Assets
Derivative assets - interest rate swaps	25,740	8,318
Liabilities
Derivative liabilities - interest rate swaps	26,162	8,318
Recurring \| Level 1
Assets
Fair Value	0	0
Equity security	131	148
Recurring \| Level 1 \| U.S. government and agency securities
Assets
Fair Value	0	0
Recurring \| Level 1 \| Municipal securities
Assets
Fair Value	0	0
Recurring \| Level 1 \| Residential mortgage-backed securities
Assets
Fair Value	0	0
Recurring \| Level 1 \| Commercial mortgage-backed securities
Assets
Fair Value	0	0
Recurring \| Level 1 \| Other asset-backed securities
Assets
Fair Value	0	0
Recurring \| Level 1 \| Other Security Investments
Assets
Fair Value		0
Recurring \| Level 1 \| Interest Rate Swap
Assets
Derivative assets - interest rate swaps	0	0
Liabilities
Derivative liabilities - interest rate swaps	0	0
Recurring \| Level 2
Assets
Fair Value	802,163	952,312
Equity security	0	0
Recurring \| Level 2 \| U.S. government and agency securities
Assets
Fair Value		105,223
Recurring \| Level 2 \| Municipal securities
Assets
Fair Value		133,014
Recurring \| Level 2 \| Residential mortgage-backed securities
Assets
Fair Value		339,608
Recurring \| Level 2 \| Commercial mortgage-backed securities
Assets
Fair Value		327,095
Recurring \| Level 2 \| Other asset-backed securities
Assets
Fair Value		24,194
Recurring \| Level 2 \| Other Security Investments
Assets
Fair Value		23,178
Recurring \| Level 2 \| Interest Rate Swap
Assets
Derivative assets - interest rate swaps	25,740	8,318
Liabilities
Derivative liabilities - interest rate swaps	26,162	8,318
Recurring \| Level 3
Assets
Fair Value	0	0
Equity security	0	0
Recurring \| Level 3 \| U.S. government and agency securities
Assets
Fair Value	0	0
Recurring \| Level 3 \| Municipal securities
Assets
Fair Value	0	0
Recurring \| Level 3 \| Residential mortgage-backed securities
Assets
Fair Value	0	0
Recurring \| Level 3 \| Commercial mortgage-backed securities
Assets
Fair Value	0	0
Recurring \| Level 3 \| Other asset-backed securities
Assets
Fair Value	0	0
Recurring \| Level 3 \| Other Security Investments
Assets
Fair Value	0	0
Recurring \| Level 3 \| Interest Rate Swap
Assets
Derivative assets - interest rate swaps	0	0
Liabilities
Derivative liabilities - interest rate swaps	$ 0	$ 0

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Amount of 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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