Fair Value Disclosures (Assets Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 14,094,000	$ 39,506,000
Other-than-temporary impairment		(388,000)	[1]
Included in other comprehensive income (before taxes)	141,000	(392,000)
Ending Balance	14,235,000	38,726,000
Other Equity Securities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	2,797,000	3,156,000
Other-than-temporary impairment		0	[1]
Included in other comprehensive income (before taxes)	19,000	1,000
Ending Balance	2,816,000	3,157,000
Other Structured Financial Products [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	11,297,000	9,550,000
Other-than-temporary impairment		0	[1]
Included in other comprehensive income (before taxes)	122,000	427,000
Ending Balance	11,419,000	9,977,000
Non-Agency Residential Mortgage-Backed Securities [Member]
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	0	26,800,000
Other-than-temporary impairment		(388,000)	[1]
Included in other comprehensive income (before taxes)	0	(820,000)
Ending Balance	$ 0	$ 25,592,000

[1] Included in noninterest income, net impairment losses recognized in earnings.