Real Estate and Lending Activities - Summary of Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Loans [Line Items]
Loans, Balance	$ 1,910,522	$ 1,928,525
Mortgage Loans [Member]
Loans [Line Items]
Loans, Balance	1,428,069	1,778,316
Acquisition Loans [Member]
Loans [Line Items]
Loans, Balance	117,376	118,448
Working Capital and Other Loans [Member]
Loans [Line Items]
Loans, Balance	$ 365,077	$ 31,761

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.

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

Name:	us-gaap_LoansReceivableNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant