Mortgage Servicing Rights ("MSRs") (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of the period	$ 85,638	$ 75,183
Additions from loans sold with servicing retained	9,447	6,580
Estimate of changes in fair value due to:
Payoffs and paydowns	(7,024)	(1,997)
Changes in valuation inputs or assumptions	(14,557)	(8,744)
Fair value at end of the period	73,504	71,022
Unpaid principal balance of mortgage loans serviced for others	$ 8,314,634	$ 7,014,269

This is the sum of principal amount outstanding for both securitized and unsecuritized loans of all types.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
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- Definition

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of increase (decrease) in fair value from changes in the inputs, assumptions, or model used to calculate the fair value of the contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 3
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- References

No definition available.

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- Definition

Decrease in servicing assets subsequently measured at fair value resulting from conveyance of servicing rights to unrelated parties.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 50
-Section 50
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-URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122625-111746

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- Definition

Servicing Assets At Fair Value, Additions From Loans Sold With Servicing Retained

+ References

No definition available.

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