Loans Receivable - Summary of Details Overall Statistics for Loans Receivable Portfolio (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2018 USD ($) Loans	Dec. 31, 2017 USD ($) Loans
Loans and Leases Receivable, Net Amount [Abstract]
Number of loans \| Loans	17	3
Principal balance	$ 238,979	$ 49,850
Net book value	239,207	49,929
Unfunded loan commitments	$ 38,324	$ 12,620
Weighted-average cash coupon	7.28%	5.63%
Weighted-average all-in yield	7.48%	6.28%
Weighted-average maximum maturity (years)	3 years 7 months 6 days	3 years 6 months

Financing receivable, number of loans.

No definition available.

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- Definition

Loan maturity period.

+ References

No definition available.

+ Details

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- Definition

Weighted average cash coupon rate.

+ References

No definition available.

+ Details

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- Definition

The calculated weighted average effective interest rate on the securities.

+ References

No definition available.

+ Details

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- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Reflects the unfunded portion of contractual agreements to lend funds to borrowers for loans whose terms have been modified by troubled debt restructuring.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18794-111554

+ Details

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Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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- Definition

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes loans held for sale. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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