Fair Value Measurements (Schedule Of Valuation Methodology And Unobservable Inputs) (Detail) (USD $) In Thousands, unless otherwise specified		9 Months Ended
	Dec. 31, 2012 Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2013 Discount for costs to sell [Member]	Sep. 30, 2013 Minimum [Member] Discount for date appraisal [Member]	Sep. 30, 2013 Minimum [Member] Discount for costs to sell [Member]	Sep. 30, 2013 Minimum [Member] Discount for appraisal type [Member]	Sep. 30, 2013 Minimum [Member] Prepayment speeds [Member]	Sep. 30, 2013 Minimum [Member] Discount rate [Member]	Sep. 30, 2013 Maximum [Member] Discount for date appraisal [Member]	Sep. 30, 2013 Maximum [Member] Discount for costs to sell [Member]	Sep. 30, 2013 Maximum [Member] Discount for appraisal type [Member]	Sep. 30, 2013 Maximum [Member] Prepayment speeds [Member]	Sep. 30, 2013 Maximum [Member] Discount rate [Member]	Sep. 30, 2013 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Nonrecurring [Member]		Dec. 31, 2012 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Nonrecurring [Member]		Sep. 30, 2013 Other Real Estate Owned [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2013 Impaired Loans [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Nonrecurring [Member]
Fair Value Measurements [Line Items]
Impaired Loans, Fair Value	$ 11,851,567												$ 12,410,295		$ 12,005,555			$ 41,177
Alternative investments																	7,919
Mortgage Servicing Assets													$ 25,496	[1]	$ 15,881	[1]
Range of Inputs		8.00%	0.00%	3.00%	25.00%	6.70%	3.10%	30.00%	8.00%	50.00%	26.60%	6.00%

[1] The carrying amount of mortgage servicing assets is net of $0.4 million and $1.8 million reserves at September 30, 2013 and December 31, 2012, respectively. The estimated fair value does not include such adjustments.