Subsequent Events - Additional Information (Detail) - DCT and DCT OP [Member] $ in Billions	Apr. 29, 2018 USD ($)
Subsequent Event [Line Items]
Business acquisition, date of acquisition agreement	Apr. 29, 2018
Value of common stock issued as consideration	$ 8.2
Business acquisition stock conversion ratio	1.02

Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Name:	us-gaap_BusinessAcquisitionEquityInterestIssuedOrIssuableValueAssigned
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant