MORTGAGE SERVICING RIGHTS - Summary of Components of Net Carrying Value of Acquired and Originated MSRs (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
MSRs
Mortgage Servicing Rights Acquired and Originated
Gross carrying value	$ 1,003,852	$ 817,964
Accumulated amortization	(369,096)	(296,034)
Net carrying value	634,756	521,930
Acquired MSRs
Mortgage Servicing Rights Acquired and Originated
Gross carrying value	183,715	175,934
Accumulated amortization	(121,643)	(104,264)
Net carrying value	62,072	71,670
Originated MSRs
Mortgage Servicing Rights Acquired and Originated
Gross carrying value	820,137	642,030
Accumulated amortization	(247,453)	(191,770)
Net carrying value	$ 572,684	$ 450,260

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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