Significant Accounting Policies and Basis of Presentation - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule Of Accounting Policies [Line Items]
Notional amount	$ 201.0	$ 150.3
Derivatives Not Designated as Hedging Instruments [Member] | Credit Derivatives [Member]
Schedule Of Accounting Policies [Line Items]
Notional amount	13.4
Cash Flow Hedges [Member]
Schedule Of Accounting Policies [Line Items]
Notional amount	$ 150.0