Selected Quarterly Financial Data (Unaudited) - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Dec. 31, 2013	Mar. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Reversal of litigation judgment reserve	$ 1.1	$ 2.2
Accrual of litigation judgment expense	$ 2.6

Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees.

No definition available.

Name:	us-gaap_LitigationSettlementExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration