Notes Receivable - Loans Receivable on Real Estate (Parenthetical) (Detail) - USD ($) $ in Thousands	1 Months Ended	6 Months Ended
Apr. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
Accounts Notes And Loans Receivable [Line Items]
Repayment of notes receivable	$ 30,600	$ 31,068	$ 305
Notes Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Debt instrument maturity date	2017-09

The cash inflow associated with principal collections from a borrowing supported by a written promise to pay an obligation.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

Name:	us-gaap_ProceedsFromCollectionOfNotesReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration