Fair Value of Financial Instruments - Fair Value Measured on a Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Securities available for sale, fair value	$ 620,956	$ 772,500
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, fair value	386,235	523,849
Other Securities [Member]
Securities available for sale, fair value	1,149	1,332
Fair Value, Measurements, Recurring [Member]
Total assets	621,372	774,852
Financial and Nonfinancial Liabilities, Fair Value Disclosure	107,882	64,037
Fair Value, Measurements, Recurring [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities available for sale, fair value	386,235	523,849
Fair Value, Measurements, Recurring [Member] \| Other Securities [Member]
Securities available for sale, fair value	234,721	248,651
Fair Value, Measurements, Recurring [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	416	2,352
Interest Rate Swaps, Net Amount	69,595	19,653
Fair Value, Measurements, Recurring [Member] \| Junior Subordinated Debentures [Member]
Borrowings	38,287	44,384
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Total assets	12,691	12,216
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	12,691	12,216
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	607,532	761,304
Financial and Nonfinancial Liabilities, Fair Value Disclosure	69,595	19,653
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Collateralized Mortgage Backed Securities [Member]
Securities available for sale, fair value	386,235	523,849
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Other Securities [Member]
Securities available for sale, fair value	220,881	235,103
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member] \| Interest Rate Swap [Member]
Interest Rate Swaps, Net Amount	416	2,352
Interest Rate Swaps, Net Amount	69,595	19,653
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	1,149	1,332
Financial and Nonfinancial Liabilities, Fair Value Disclosure	38,287	44,384
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	1,149	1,332
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	$ 38,287	$ 44,384

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 portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Fair value of financial and nonfinancial obligations.

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