Summary Of Significant Accounting Policies (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Summary Of Significant Accounting Policies [Line Items]
Common securities	100.00%
Gross loans comprised of commercial mortgage loans, percentage	53.10%
Gross loans comprised of commercial loans, percentage	26.50%
Residential mortgages properties, percentage	65.00%
Total deposits comprised of time deposit, percentage	48.40%
Jumbo CDs deposit with the company for two years or more, percentage	57.10%
Time Deposits	$ 4,331,326,000
Federal Home Loan Bank stock	52,989,000	63,873,000
Minimum stock requirement on outstanding FHLB borrowings, shares	250,000
Outstanding FHLB borrowings	225,000,000
Company owned shares of FHLB stock	529,888
Maximum homogenous portfolio loan amount	500,000
Venture capital investments, limited partnership interests represent ownership, maximum percentage	5.00%
Unamortized core deposit premium	10,600,000	16,400,000
Core deposit premium, accumulated amortization	49,800,000	44,100,000
Amortization of core deposit intangibles	5,859,000	5,958,000	6,636,000
Estimated aggregate amortization of core deposit premiums, 2012	5,700,000
Estimated aggregate amortization of core deposit premiums, 2013	4,500,000
Estimated aggregate amortization of core deposit premiums, 2014 and thereafter	400,000
Option compensation expense	1,000,000	3,000,000	5,400,000
Unrecognized stock-based compensation expense related to stock options	904,000
Unrecognized stock-based compensation expense related to stock options expected to be recognized period, years	1.2
Time Deposit [Member]
Summary Of Significant Accounting Policies [Line Items]
Time Deposits	$ 100,000