Loan Sales and Servicing - Loans Transferred to Held for Sale and Loans Sold (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans transferred from held for investment to held for sale	$ 0	$ 1,196,883
Loans and Loans Held for Sale Excluding Loans Originated for Sale in Secondary Market
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans transferred from held for investment to held for sale	0	1,196,883
Charge-offs on loans recognized at transfer from held for investment to held for sale	0	0
Loans and loans held for sale sold	$ 0	$ 144,674

Value of loans and leases held in the entity's portfolio transferred to loans and leases held-for-sale in noncash transactions.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration