Securities Available-for-Sale - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014 security	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Number of debt securities on which unrealized losses were primarily attributable to changes in interest	41
Unrealized losses reclassified out of accumulated other comprehensive income into earnings	$ 0
Net unrealized gains (losses) included in accumulated other comprehensive loss, net of tax	2,300,000	(600,000)
Gross unrealized gains, net of taxes	5,400,000	4,400,000
Gross unrealized losses, net of taxes	3,100,000	5,000,000
Carrying values of securities	$ 345,900,000	$ 243,200,000