Loans Receivable (Narrative) (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Percentage of covered loan under loss share agreements	80.00%	80.00%
Percentage of acquisitions losses under loss share agreements	95.00%	95.00%
Financing Receivable, Recorded Investment	$ 5,737,969,000	$ 5,737,969,000	$ 4,452,585,000
Financing Receivable, Recorded Investment, Current	5,642,858,000	5,642,858,000	4,388,324,000
Financing Receivable, Recorded Investment, Past Due	125,017,000	125,017,000	64,261,000
Loans Covered By Loss Share Agreement	1,462,677,000	1,462,677,000	1,582,747,000
Total loans on nonaccrual status	93,635,000	93,635,000	49,496,000
Provision for loan losses	2,639,000	4,409,000
Indemnification asset for portion of losses recoverable	19,922,000	26,706,000
Non-Covered Loan [Member]
Financing Receivable, Recorded Investment	5,737,969,000	5,737,969,000	4,452,585,000
Non-Covered Loan [Member] | Residential Mortgage Loans [Member]
Financing Receivable, Recorded Investment	329,716,000	329,716,000	369,986,000
Non-Covered Loan [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment	4,197,325,000	4,197,325,000	3,123,096,000
Non-Covered Loan [Member] | Commercial Loans [Member] | Total Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment	2,403,000	2,403,000
Non-Covered Loan [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment	1,210,928,000	1,210,928,000	959,503,000
Non-Covered Loan [Member] | Commercial Real Estate Loans [Member] | Total Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment	54,558,000	54,558,000
Non-Covered Loan [Member] | Other Consumer [Member]
Financing Receivable, Recorded Investment, Current	166,468,000	166,468,000	99,420,000
Financing Receivable, Recorded Investment, Past Due	10,359,000	10,359,000	6,096,000
Non-Covered Loan [Member] | Other Consumer [Member] | Total Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment	25,000	25,000
Non-Covered Loan [Member] | Home equity [Member]
Financing Receivable, Recorded Investment, Current	737,851,000	737,851,000	551,101,000
Financing Receivable, Recorded Investment, Past Due	4,709,000	4,709,000	4,648,000
Non-Covered Loan [Member] | Home equity [Member] | Total Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment	3,520,000	3,520,000
Non-Covered Loan [Member] | Total Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment	60,506,000	60,506,000	17,471,000
Financing Receivable, Recorded Investment, Current	33,307,000	33,307,000	10,215,000
Financing receivable greater than 30 days past due	27,199,000	27,199,000
Financing Receivable, Recorded Investment, Past Due			7,257,000
Total loans on nonaccrual status	29,266,000	29,266,000	2,504,000
Covered Loan [Member] | Commercial Loans [Member] | Total Troubled Debt Restructurings [Member]
Loans Covered By Loss Share Agreement	2,276,000	2,276,000
Covered Loan [Member] | Commercial Real Estate Loans [Member] | Total Troubled Debt Restructurings [Member]
Loans Covered By Loss Share Agreement	46,374,000	46,374,000
Covered Loan [Member] | Other Consumer [Member]
Loans Covered By Loss Share Agreement	11,000	11,000
Covered Loan [Member] | Mortgage Loans on Real Estate [Member] | Total Troubled Debt Restructurings [Member]
Loans Covered By Loss Share Agreement	10,935,000	10,935,000
Covered Loan [Member] | Home equity [Member] | Total Troubled Debt Restructurings [Member]
Loans Covered By Loss Share Agreement	17,314,000	17,314,000
Covered Loan [Member] | Total Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment, Current	47,004,000	47,004,000
Financing receivable greater than 30 days past due	29,906,000	29,906,000
Loans Covered By Loss Share Agreement	76,910,000	76,910,000
Residential Mortgage Loans [Member]
Loans Covered By Loss Share Agreement	234,317,000	234,317,000	261,386,000
Commercial Loans [Member]
Loans Covered By Loss Share Agreement	964,224,000	964,224,000	1,039,867,000
Commercial Loans [Member] | Total Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment			56,000
Consumer Loans [Member]
Loans Covered By Loss Share Agreement	264,136,000	264,136,000	281,494,000
Commercial Real Estate Loans [Member] | Total Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment			16,368,000
Construction Loans [Member] | Total Troubled Debt Restructurings [Member]
Financing Receivable, Recorded Investment			$ 1,047,000