Secured Debt Agreements, Net - Summary of Key Terms of Credit Facilities (Parenthetical) (Detail)	6 Months Ended
Jun. 30, 2019
Barclays [Member] \| Credit Facilities [Member]
Line of Credit Facility [Line Items]
Maturity period	Includes four one-year extension options which may be exercised at our sole discretion.

This describes the time frame of the terms of the entity's repurchase agreements.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(m)(1)(i)(A))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Name:	us-gaap_RepurchaseAgreementsMaturities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration