Allowance for Loan Losses Details Textual (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011
Allowance For Loan And Lease Losses [Line Items]
Provision for loan and lease losses - acquired loans	$ 2,033,000	$ 0	$ 2,033,000	$ 0
Loan Commitments	5,578,342,000	4,094,181,000	5,578,342,000	4,094,181,000		4,151,541,000
Minimum Non Performing Substandard Loans Outstanding for Allowance for Credit Losses	300,000		300,000
Minimum Non Performing Substandard Doubtful Loans Outstanding for Allowance for Credit Losses	100,000		100,000
Nonaccrual Non-reaffirmed Bankruptcies	8,800,000		8,800,000			7,700,000
Covered Loans
Allowance For Loan And Lease Losses [Line Items]
Loans and Leases Receivable, Allowance, Covered	45,544,000	43,644,000	45,544,000	43,644,000	49,069,000	43,255,000	42,606,000	36,417,000
Provision for Loan Losses Before Benefit Attributable to FDIC Loss Share Agreements	2,855,000	7,698,000	19,009,000	28,177,000
Allowance for Loan and Lease Losses, Write-offs	(6,380,000)	(6,660,000)	(16,720,000)	(20,950,000)
Benefit Attributable to FDIC Loss Share Agreements	(1,032,000)	(1,484,000)	(8,890,000)	(12,601,000)
Provision for Loan Lease and Other Losses Covered	1,823,000	6,214,000	10,119,000	15,576,000
Loans with No Related Allowance
Allowance For Loan And Lease Losses [Line Items]
Loan Commitments	$ 200,000		$ 200,000