Fair Value of Financial Instruments - Fair Value Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Securities available for sale, fair value	$ 796,799	$ 647,974
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	0		$ 0
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, fair value	584,145	404,460
Other Securities [Member]
Securities available for sale, fair value	1,548	1,295
Fair Value, Measurements, Recurring [Member]
Total assets	804,192	649,293
Financial and Nonfinancial Liabilities, Fair Value Disclosure	84,774	104,123
Fair Value, Measurements, Recurring [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities available for sale, fair value	584,145	404,460
Fair Value, Measurements, Recurring [Member] \| Other Securities [Member]
Securities available for sale, fair value	212,654	243,514
Fair Value, Measurements, Recurring [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	7,393	1,319
Interest Rate Swaps, Net Amount	33,196	60,987
Fair Value, Measurements, Recurring [Member] \| Junior Subordinated Debentures [Member]
Borrowings	51,578	43,136
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Total assets	12,572	12,703
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities available for sale, fair value	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Other Securities [Member]
Securities available for sale, fair value	12,572	12,703
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	0	0
Interest Rate Swaps, Net Amount	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member] \| Junior Subordinated Debentures [Member]
Borrowings	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Total assets	790,072	635,295
Financial and Nonfinancial Liabilities, Fair Value Disclosure	33,196	60,987
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities available for sale, fair value	584,145	404,460
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Other Securities [Member]
Securities available for sale, fair value	198,534	229,516
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	7,393	1,319
Interest Rate Swaps, Net Amount	33,196	60,987
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Junior Subordinated Debentures [Member]
Borrowings	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Total assets	1,548	1,295
Financial and Nonfinancial Liabilities, Fair Value Disclosure	51,578	43,136
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities available for sale, fair value	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Other Securities [Member]
Securities available for sale, fair value	1,548	1,295
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	0	0
Interest Rate Swaps, Net Amount	0	0
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member] \| Junior Subordinated Debentures [Member]
Borrowings	51,578	43,136
Fair Value, Measurements, Nonrecurring [Member]
Total assets	11,614	11,980
Financial and Nonfinancial Liabilities, Fair Value Disclosure	0	0
Fair Value, Measurements, Nonrecurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Total assets	0	0
Fair Value, Measurements, Nonrecurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Total assets	0	0
Fair Value, Measurements, Nonrecurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Total assets	$ 11,614	$ 11,980

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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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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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Fair value of financial and nonfinancial obligations.

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