Mortgage Loans - Schedule of Troubled Debt Restructuring Mortgage Loan Information (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) loan	Dec. 31, 2018 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	3	3
Recorded Investment Pre-Modification	$ 59,459	$ 55,815
Recorded Investment Post Modification	$ 59,459	$ 55,815
Office
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	2	1
Recorded Investment Pre-Modification	$ 21,211	$ 5,164
Recorded Investment Post Modification	$ 21,211	$ 5,164
Retail
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	1	1
Recorded Investment Pre-Modification	$ 38,248	$ 42,448
Recorded Investment Post Modification	$ 38,248	$ 42,448
Other (Hotel/Motel)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Loans \| loan	0	1
Recorded Investment Pre-Modification	$ 0	$ 8,203
Recorded Investment Post Modification	$ 0	$ 8,203

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No definition available.

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

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Amount, after troubled debt restructuring, of modified financing receivable.

+ References

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- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

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