Share-Based Compensation (Detail) - Salary Stock Awards Granted (Salary Stock Awards, USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Salary Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted	0	8,693,000	10,983,000
Weighted-average price (in Dollars per share)	$ 0.00	$ 14.30	$ 11.51

Net number of share options (or share units) granted during the period.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration