Disclosures about Fair Value of Assets and Liabilities - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Disclosures about Fair Value of Assets and Liabilities
Mortgage loans in process of securitization	$ 465,157	$ 269,891
Available for sale securities	339,053	290,243
Loans held for sale	18,938	19,592
Mortgage servicing rights	69,978	74,387
Recurring
Disclosures about Fair Value of Assets and Liabilities
Mortgage loans in process of securitization	465,157	269,891
Loans held for sale	18,938	19,592
Mortgage servicing rights	69,978	74,387
Recurring \| Interest Rate Lock Commitments
Disclosures about Fair Value of Assets and Liabilities
Derivative assets	2,079	186
Derivative liabilities	80
Recurring \| Forward Contracts
Disclosures about Fair Value of Assets and Liabilities
Derivative assets	96
Derivative liabilities	1,273	27
Recurring \| Interest rate swaps
Disclosures about Fair Value of Assets and Liabilities
Derivative assets	3,214	511
Derivative liabilities	3,214	511
Level 2 \| Recurring
Disclosures about Fair Value of Assets and Liabilities
Mortgage loans in process of securitization	465,157	269,891
Loans held for sale	18,938	19,592
Level 2 \| Recurring \| Forward Contracts
Disclosures about Fair Value of Assets and Liabilities
Derivative assets	96
Derivative liabilities	1,273	27
Level 2 \| Recurring \| Interest rate swaps
Disclosures about Fair Value of Assets and Liabilities
Derivative assets	3,214	511
Derivative liabilities	3,214	511
Level 3 \| Interest Rate Lock Commitments
Disclosures about Fair Value of Assets and Liabilities
Derivative assets	2,079	186
Derivative liabilities	80
Level 3 \| Recurring
Disclosures about Fair Value of Assets and Liabilities
Mortgage servicing rights	69,978	74,387
Level 3 \| Recurring \| Interest Rate Lock Commitments
Disclosures about Fair Value of Assets and Liabilities
Derivative assets	2,079	186
Derivative liabilities	80
Treasury notes \| Recurring
Disclosures about Fair Value of Assets and Liabilities
Available for sale securities	2,043	4,765
Treasury notes \| Level 1 \| Recurring
Disclosures about Fair Value of Assets and Liabilities
Available for sale securities	2,043	4,765
Federal agencies
Disclosures about Fair Value of Assets and Liabilities
Available for sale securities	306,575	244,973
Federal agencies \| Recurring
Disclosures about Fair Value of Assets and Liabilities
Available for sale securities	306,575	244,973
Federal agencies \| Level 2 \| Recurring
Disclosures about Fair Value of Assets and Liabilities
Available for sale securities	306,575	244,973
Municipals \| Recurring
Disclosures about Fair Value of Assets and Liabilities
Available for sale securities	5,951	5,937
Municipals \| Level 2 \| Recurring
Disclosures about Fair Value of Assets and Liabilities
Available for sale securities	5,951	5,937
Mortgage-backed - Government-sponsored entity (GSE) - residential
Disclosures about Fair Value of Assets and Liabilities
Available for sale securities	24,484	34,568
Mortgage-backed - Government-sponsored entity (GSE) - residential \| Recurring
Disclosures about Fair Value of Assets and Liabilities
Available for sale securities	24,484	34,568
Mortgage-backed - Government-sponsored entity (GSE) - residential \| Level 2 \| Recurring
Disclosures about Fair Value of Assets and Liabilities
Available for sale securities	$ 24,484	$ 34,568

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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
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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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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-Section 55
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Fair value, after the effects of master netting arrangements, of a financial liability or 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 liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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