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Amount, before accumulated amortization, of capitalized implementation cost from hosting arrangement that is service contract.

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Present value of lessee's discounted obligation for lease payments from operating lease.

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SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Cash Equivalents and Recent Accounting Pronouncements (Detail)		12 Months Ended
	Jan. 01, 2019 USD ($)	Dec. 31, 2019 USD ($) loan	Jan. 01, 2020 USD ($)	Dec. 31, 2018 USD ($) loan	Dec. 31, 2017 USD ($)
Cash and Cash Equivalents
Cash equivalents		$ 0		$ 0
Recently Announced Accounting Pronouncements
Cumulative-effect adjustment for adoption of ASU 2016-02, net of tax		(1,002,000)
Operating lease right-of-use assets		22,300,000
Operating lease liabilities		$ 28,156,000
Number of loans held for investment \| loan		22		14
Allowance for risk-sharing obligations		$ 11,471,000		$ 4,622,000	$ 3,783,000
Retained earnings		$ 796,775,000		$ 666,752,000
ASU 2016-02
Recently Announced Accounting Pronouncements
Lease, Practical Expedients, Package	true
Lease, Practical Expedient, Use of Hindsight	true
Cumulative-effect adjustment for adoption of ASU 2016-02, net of tax	$ 1,000,000.0
Mortgage Loans
Concentrations of Credit Risk
Period of originated loans within which they are transferred or sold		60 days
Forecast \| ASU 2016-13 \| Minimum
Recently Announced Accounting Pronouncements
Allowance for risk-sharing obligations			$ 30,000,000
Retained earnings			25,000,000
Forecast \| ASU 2016-13 \| Maximum
Recently Announced Accounting Pronouncements
Allowance for risk-sharing obligations			35,000,000
Retained earnings			$ 30,000,000
ASU 2018-15 \| Adjustments for New Accounting Principle, Early Adoption
Recently Announced Accounting Pronouncements
Capitalized implementation costs of hosting arrangement service contract		$ 6,200,000