Earnings Per Share (Outstanding Common Stock Equivalents That Were Anti-Dilutive) (Parenthetical) (Detail) (USD $)	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Exercise price for warrants outstanding	$ 22.5	$ 22.5
3 1/2% Convertible Notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Convertible senior notes interest percentage	3.50%	3.50%

Interest rate stated in the contractual debt agreement.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant