Derivative Instruments and Hedging Activities - Income for Derivatives Not Designated as Hedging Instruments (Detail) (Not Designated as Hedging Instrument [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Income for derivatives not designated as hedging instruments	$ 150	$ (555)	$ 235	$ (785)
Net Gain (Loss) on Mortgage Banking Activities [Member] | Interest Rate Locks with Customers [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Income for derivatives not designated as hedging instruments	350	(1,549)	448	(1,611)
Net Gain (Loss) on Mortgage Banking Activities [Member] | Forward Loan Sale Commitments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Income for derivatives not designated as hedging instruments	$ (200)	$ 994	$ (213)	$ 826