Mortgage Servicing Rights and Mortgage Servicing Liabilities - Servicing, Late, Ancillary and Other Fees Relating to MSRs (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Contractually Specified Servicing Fees, Amount	$ 147,182	$ 126,416	$ 421,536	$ 345,231
Ancillary and other fees
Ancillary Fee Income Generated by Servicing Financial Assets, Amount	17,009	15,548	44,817	38,616
Bank Servicing Fees	109,703	78,081	340,181	199,157
Mortgage servicing rights
Contractually Specified Servicing Fees, Amount	147,182	126,416	421,536	345,231
Ancillary and other fees
Late Fee Income Generated by Servicing Financial Assets, Amount	5,087	6,326	19,595	18,915
Ancillary Fee Income Generated by Servicing Financial Assets, Amount	1,244	1,270	4,620	3,296
Bank Servicing Fees	$ 153,513	$ 134,012	$ 445,751	$ 367,442

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No definition available.

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- Definition

Amount of revenue from servicing real estate mortgages, credit cards, and other financial assets held by others. Includes premiums received in lieu of regular servicing fee.

+ References

No definition available.

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- Definition

All amounts that are due to the servicer of a financial asset, excluding contractually specified servicing fees and late fees.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 50
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=68078379&loc=d3e122596-111746

+ Details

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- Definition

All amounts that, per contract, are due to the servicer in exchange for servicing the financial asset and would no longer be received by a servicer if the beneficial owners of the serviced assets (or their trustees or agents) were to exercise their actual or potential authority under the contract to shift the servicing to another servicer. Depending on the servicing contract, those fees may include some or all of the difference between the interest rate collected on the asset being serviced and the rate to be paid to the beneficial owners of the asset.

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+ Details

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- Definition

All amounts that are due to the servicer of a financial asset as a result of the debt holder not meeting the monthly payment terms.

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+ Details

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