Allowance For Loan Losses And Reserve For Unfunded Commitments (Reserve For Unfunded Commitments) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Balance at beginning of period	$ 8,210	[1]	$ 8,119	[1]	$ 7,277	[1]	$ 8,119	[1]
Provision for unfunded commitments		[1]	(1,133)	[1]	933	[1]	(1,133)	[1]
Balance at end of period	8,210	[1]	6,986	[1]	8,210	[1]	6,986	[1]
Unfunded commitments, excluding covered assets, at period end	$ 4,552,903	[1]	$ 3,810,271	[1]	$ 4,552,903	[1]	$ 3,810,271	[1]

[1] Unfunded commitments include commitments to extend credit, standby letters of credit and commercial letters of credit