Premises and Equipment - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property Plant And Equipment Useful Life And Values [Abstract]
Depreciation expense	$ 15,558	$ 13,937	$ 12,457
Operating leases, expiration date	2045
Rental expense	10,443	8,784	6,960
Minimum rental commitments	$ 66,055