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Loans Held for Sale, at Fair Value - Additional Information (Detail) - USD ($) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018 | Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Maximum number of days loans held for sale are typically sold |  |  | 45 days |  |
Loans held for sale in nonaccrual status | $ 0 |  | $ 0 |  | $ 0
Management Services, Servicing Fees and Other [Member] |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Interest income on Loans held for sale | 6,500,000 | $ 5,000,000.0 | 15,100,000 | $ 9,700,000 |
Gains (Loss) from Mortgage Banking Activities, Net [Member] |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Gains (loss) recognized for fair value adjustments on loans held for sale | 12,400,000 | $ (7,800,000) | 25,700,000 | $ 7,300,000 |
Greater Than 90 Days Past Due [Member] |  |  |  |  |
Accounts Notes And Loans Receivable [Line Items] |  |  |  |  |
Loans held for sale past due | $ 0 |  | $ 0 |  | $ 0

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- Definition Gains (losses) recognized for fair value adjustments on loans held for sale. + References No definition available. + Details
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- Definition Maximum period of loans held for sale sold. + References No definition available. + Details
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- Definition Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524 + Details
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- Definition Recorded Investment in financing receivables that are past due at the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7A -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524 + Details
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- Definition Interest and fee income from mortgage loans considered to be held-for-sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.1) -URI http://asc.fasb.org/extlink&oid=114873765&loc=SL114874048-224260 + Details
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