Derivatives - Credit Value Adjustment Recorded Related to Notional Amount of Derivatives Outstanding (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Cash Flow Hedging [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	$ (26)	$ 0
Derivative, Notional Amount	100,000	0
Fair Value Hedging [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	252	77
Credit Default Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	113,296	82,197
Interest Rate Cap [Member]
Derivative [Line Items]
Derivative, Notional Amount	6,938	7,500
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	297,347	274,718
Credit Default Swap, Selling Protection [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ (24,796)	$ (19,161)