Related Party Transactions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Related Party Transactions [Abstract]
Undistributed earnings	$ 3

Amount of consolidated retained earnings that represent undistributed (not yet received) earnings from 50% or less owned persons accounted for by the equity method (equity method investees).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 20

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6462270&loc=d3e57205-112772

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