Derivatives - Schedule of Gains (Losses) Included in the Consolidated Statements of Income Related to Derivative Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Derivatives Fair Value [Line Items]
Gains (losses) on derivative financial instruments	$ 6,325	$ (378)
Derivatives Not Designated As Hedging Instruments \| Included in Mortgage Banking Income \| Interest rate-lock commitments
Derivatives Fair Value [Line Items]
Gains (losses) on derivative financial instruments	3,411	2,942
Derivatives Not Designated As Hedging Instruments \| Included in Mortgage Banking Income \| Forward commitments
Derivatives Fair Value [Line Items]
Gains (losses) on derivative financial instruments	5,318	$ (3,320)
Derivatives Not Designated As Hedging Instruments \| Included in Mortgage Banking Income \| Futures Contracts
Derivatives Fair Value [Line Items]
Gains (losses) on derivative financial instruments	(2,447)
Derivatives Not Designated As Hedging Instruments \| Included in Mortgage Banking Income \| Option Contracts
Derivatives Fair Value [Line Items]
Gains (losses) on derivative financial instruments	43
Designated as Hedging
Derivatives Fair Value [Line Items]
Amount of gain reclassified from other comprehensive income and recognized in interest expense on long-term debt	$ (32)

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5618551-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a),(c),(d),(e)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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- Definition

The effective portion of gain reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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- Definition

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.

+ References

No definition available.

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