Capital Stock - Additional Information (Detail)		12 Months Ended
Nov. 10, 2015 shares	Dec. 31, 2015 Vote shares
Equity [Abstract]
Preference shares included in authorized capital stock		99,760,000
Shares issued or outstanding		0
Number of votes per share \| Vote		1
Number of common stock shares to be purchased under the Bid	40,000,000
Percentage of issued and outstanding common shares	9.90%
Commencement date of Bid		Nov. 13, 2015
Termination date of Bid		Nov. 12, 2016

Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.28)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29
-Article 5

Name:	us-gaap_PreferredStockSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant