Fair Value Measurements (Summary Of Changes In Level 3 Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	$ 201,888	$ 198,706	$ 202,476	$ 204,301
Total gains or losses (realized /unrealized), included in earnings	1,482	2,600	5,596	3,662
Total gains or losses (realized /unrealized), included in other comprehensive income	520	(340)	(4,938)	(1,611)
Investment securities called	(3,000)	(1,025)	(3,350)	(6,943)
Discount accretion	147	98	207	405
Purchase of private equity securities		3,060	3,275	3,239
Sale / paydown of private equity securities	(7,845)		(10,279)
Capitalized interest/dividends	15	1	192	44
Purchase of risk participation agreement		(275)	28	79
Sales of risk participation agreements				(351)
Ending balance	193,207	202,825	193,207	202,825
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	607	2,713	4,580	4,144
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	129,873	143,207	135,621	150,089
Total gains or losses (realized /unrealized), included in earnings	0	0	0	0
Total gains or losses (realized /unrealized), included in other comprehensive income	520	(340)	(4,938)	(1,611)
Investment securities called	(3,000)	(1,025)	(3,350)	(6,943)
Discount accretion	147	98	207	405
Purchase of private equity securities		0	0	0
Sale / paydown of private equity securities	0		0
Capitalized interest/dividends	0	0	0	0
Purchase of risk participation agreement		0	0	0
Sales of risk participation agreements				0
Ending balance	127,540	141,940	127,540	141,940
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	0	0	0	0
Private Equity Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	72,121	55,507	66,978	53,860
Total gains or losses (realized /unrealized), included in earnings	1,475	2,605	5,600	4,030
Total gains or losses (realized /unrealized), included in other comprehensive income	0	0	0	0
Investment securities called	0	0	0	0
Discount accretion	0	0	0	0
Purchase of private equity securities		3,060	3,275	3,239
Sale / paydown of private equity securities	(7,845)		(10,279)
Capitalized interest/dividends	15	1	192	44
Purchase of risk participation agreement		0	0	0
Sales of risk participation agreements				0
Ending balance	65,766	61,173	65,766	61,173
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	600	2,605	4,575	4,030
Derivative Level Three Unobservable Inputs [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning balance	(106)	(8)	(123)	352
Total gains or losses (realized /unrealized), included in earnings	7	(5)	(4)	(368)
Total gains or losses (realized /unrealized), included in other comprehensive income	0	0	0	0
Investment securities called	0	0	0	0
Discount accretion	0	0	0	0
Purchase of private equity securities		0	0	0
Sale / paydown of private equity securities	0		0
Capitalized interest/dividends	0	0	0	0
Purchase of risk participation agreement		(275)	28	79
Sales of risk participation agreements				(351)
Ending balance	(99)	(288)	(99)	(288)
Total gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets still held at period end	$ 7	$ 108	$ 5	$ 114