Contingencies - Estimated Amounts of Regular, Discharge Payments Expected to Pay and Estimated Recoveries from Charged-off Loans (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2014 USD ($)
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	$ 54,096
Estimated Discharge Payments	75,194
Estimated Total Payments	129,290
Estimated Recoveries	(4,691)
2014 [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	7,452
Estimated Discharge Payments	0
Estimated Total Payments	7,452
Estimated Recoveries	(791)
2015 [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	14,251
Estimated Discharge Payments	0
Estimated Total Payments	14,251
Estimated Recoveries	(1,200)
2016 [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	16,060
Estimated Discharge Payments	0
Estimated Total Payments	16,060
Estimated Recoveries	(1,200)
2017 [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	16,333
Estimated Discharge Payments	0
Estimated Total Payments	16,333
Estimated Recoveries	(1,200)
2018 and later [Member]
Summary Of Projections Of Estimated Payments And Recoveries [Line Items]
Estimated Regular Payments	0
Estimated Discharge Payments	75,194
Estimated Total Payments	75,194
Estimated Recoveries	$ (300)