Investment Securities - Investment Securities (Parenthetical) (Detail)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Amortized Cost And Fair Value Debt Securities [Abstract]
Federal statutory rate	35.00%
Weighted-average maturity of available-for-sale investment securities	5 years 4 months 24 days	6 years
Weighted-average yield of available-for-sale investment securities	2.52%	2.64%
Weighted average maturity of held-to-maturity investment securities	4 years 6 months	4 years 6 months
Weighted-average yield of held-to-maturity investment securities	2.00%	2.00%