MORTGAGE SERVICING RIGHTS - Schedule of Activity Related to Capitalized MSRs (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Mortgage Servicing Rights
Beginning balance			$ 521,930
Ending balance	$ 573,159		573,159
Purchase of mortgage servicing rights				$ 43,374
MSRs
Mortgage Servicing Rights
Beginning balance	562,530	$ 421,651	521,930	412,348
Additions, following the sale of loan	44,650	29,053	117,574	64,026
Purchases		44,774		44,774
Amortization	(29,325)	(23,233)	(58,224)	(45,956)
Pre-payments and write-offs	(4,696)	(4,152)	(8,121)	(7,099)
Ending balance	$ 573,159	$ 468,093	$ 573,159	$ 468,093

The cash outflow to obtain servicing rights, which contractually entitle the servicer to receive fees and ancillary revenues for performing billing, collection, disbursement and recordkeeping services in connection with a mortgage portfolio. Rights may be obtained via (1) acquisition or assumption of a servicing obligation that does not relate to financial assets of the servicer or its consolidated affiliates; or (2) by originating mortgage loans and then (a) transferring the loans to a Variable Interest Entity (VIE) in a transaction that meets the necessary transfer and classification requirements, or (b) transferring the loans in a transaction that meets the requirements for sale accounting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of other-than-temporary impairment (OTTI) applied to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

+ References

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Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Amount of amortization of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer.

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Amount of additions from purchases of new servicing assets, subsequently measured at amortized cost, from a third-party servicer.

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