Securities (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013 security	Dec. 31, 2012	Dec. 31, 2011
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities Pledged as Collateral	$ 755,300,000	$ 675,300,000
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments	34,572,000	2,748,000	3,346,000
Cost-method Investments, Realized Gain (Loss)	34,000,000
Number of CDOs Sold	1
Carrying value of CDO sold	0
Gain on sale of CDO	101,000
Other Than Temporary Impairment Credit Losses Recognized in Earnings Reductions CDO Sold	6,800,000
Held-to-maturity Securities pledged as collateral	$ 0	$ 0