Long-Term Borrowings - Components of Long-Term Borrowings (Parenthetical) (Detail) (6.625% senior notes due 2021 [Member], Senior notes [Member])	0 Months Ended	3 Months Ended	12 Months Ended
Jul. 18, 2013	Mar. 31, 2015	Dec. 31, 2014	Jul. 18, 2013
6.625% senior notes due 2021 [Member] \| Senior notes [Member]
Debt Instrument [Line Items]
Interest rate	6.625%	6.625%	6.625%	6.625%
Due date	Jul. 15, 2021	Jul. 15, 2021	Jul. 15, 2021

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

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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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant