Assets Acquired in FDIC-Assisted Acquisitions - Loan-by-Loan Basis Performance of Fair Value Adjustments (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Business Combinations [Abstract]
Adjustments needed where the Company's initial estimate of cash flows were underestimated: (recorded with a reclassification from non-accretable difference to accretable discount)	$ 5,622	$ 4,052	$ 51,003
Adjustments needed where the Company's initial estimate of cash flows were overstated: (recorded through a provision for loan losses)	1,125	1,600	7,695
Adjustments needed where the Company's initial estimate of cash flows were underestimated: (recorded with a reclassification from non-accretable difference to accretable discount)	1,124	810	10,201
Adjustments needed where the Company's initial estimate of cash flows were overstated: (recorded through a provision for loan losses)	$ 225	$ 320	$ 1,539