Real Estate and Lending Activities - Summary of Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Loans [Line Items]
Loans, Balance	$ 1,929,264	$ 1,216,121
Mortgage Loans [Member]
Loans [Line Items]
Loans, Balance	1,777,555	1,060,400
Acquisition Loans [Member]
Loans [Line Items]
Loans, Balance	119,256	121,464
Working Capital and Other Loans [Member]
Loans [Line Items]
Loans, Balance	$ 32,453	$ 34,257

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://www.xbrl.org/2003/role/presentationRef
-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