Fair Value Measurements - Assets and liabilities recorded at fair value on recurring basis (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Investment securities	$ 772,394	$ 843,363
Derivative asset	4,523	311
Derivative liability	6,297	611
U. S. agency securities
Investment securities	117,054	179,794
Residential mortgage backed securities
Investment securities	531,528	543,852
Loans held for sale	68,433	56,707
Municipal bonds
Investment securities	90,694	73,931
Corporate bonds
Investment securities	32,920	10,733
U.S. Treasury
Investment securities		34,855
Recurring
Loans held for sale	68,433	56,707
Other equity investments	198	198
Assets measured at a fair value	845,281	900,667
Derivative liability	150	86
Liabilities measured at a fair value	6,228	667
Recurring \| Interest Rate Swap
Derivative liability	1,330	203
Recurring \| Interest Rate Caps
Derivative asset	4,454	317
Derivative liability	4,748	312
Recurring \| U. S. agency securities
Investment securities	117,054	179,794
Recurring \| Residential mortgage backed securities
Investment securities	531,528	543,852
Recurring \| Municipal bonds
Investment securities	90,694	73,931
Recurring \| Corporate bonds
Investment securities	32,920	10,733
Recurring \| U.S. Treasury
Investment securities		34,855
Recurring \| Mortgage Banking Derivative \| Derivative Financial Instruments, Liability
Derivative liability		66
Recurring \| Mortgage Banking Derivative \| Derivative Financial Instruments, Assets
Derivative asset		280
Recurring \| Fair Value, Inputs, Level 2
Loans held for sale	68,433	56,707
Assets measured at a fair value	812,163	889,456
Derivative liability	150	86
Liabilities measured at a fair value	6,228	601
Recurring \| Fair Value, Inputs, Level 2 \| Interest Rate Swap
Derivative liability	1,330	203
Recurring \| Fair Value, Inputs, Level 2 \| Interest Rate Caps
Derivative asset	4,454	317
Derivative liability	4,748	312
Recurring \| Fair Value, Inputs, Level 2 \| U. S. agency securities
Investment securities	117,054	179,794
Recurring \| Fair Value, Inputs, Level 2 \| Residential mortgage backed securities
Investment securities	531,528	543,852
Recurring \| Fair Value, Inputs, Level 2 \| Municipal bonds
Investment securities	90,694	73,931
Recurring \| Fair Value, Inputs, Level 2 \| U.S. Treasury
Investment securities		34,855
Recurring \| Fair Value, Inputs, Level 3
Other equity investments	198	198
Assets measured at a fair value	33,118	11,211
Liabilities measured at a fair value		66
Recurring \| Fair Value, Inputs, Level 3 \| Corporate bonds
Investment securities	$ 32,920	10,733
Recurring \| Fair Value, Inputs, Level 3 \| Mortgage Banking Derivative \| Derivative Financial Instruments, Liability
Derivative liability		66
Recurring \| Fair Value, Inputs, Level 3 \| Mortgage Banking Derivative \| Derivative Financial Instruments, Assets
Derivative asset		$ 280

Fair value portion of other equity investments.

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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 of financial and nonfinancial obligations.

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