Fair Value (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Federal Home Loan Bank Stock and Federal Reserve Bank Stock	$ 97,500,000		$ 99,000,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Asset	11,700,000
Available for sale	1,513,157,000		2,547,876,000
Loans held for sale	465,983,000		223,638,000
Loans Receivable Held-for-sale, Net	465,983,000		273,957,000
Gain (Loss) on Mortgage Servicing Rights	(216,000)		(6,179,000)		1,125,000
Gains (Losses) on Sales of Other Real Estate	(247,000)		(16,628,000)		(26,664,000)
Servicing Asset at Fair Value, Amount	32,420,000
Mortgage servicing rights, net	32,420,000		23,102,000
Charge-offs for properties held	3,900,000		20,900,000
Contingent Consideration Liability [Roll Forward]
Beginning Balance	0
Valuation adjustments - noninterest expense - other - mergers and acquisitions	3,742,000
Ending Balance	15,442,000		0
Change During Period, Fair Value Disclosure
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans held for sale	11,447,000		7,506,000
MBS
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	1,308,838,000
Municipal Bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	204,306,000
Fair Value, Measurements, Nonrecurring | Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gain (Loss) on Sales of Loans, Net	(27,649,000)		(47,372,000)
Fair Value, Measurements, Nonrecurring | Loans | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans receivable, net	172,172,000		268,837,000
Fair Value, Measurements, Nonrecurring | OREO
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gains (Losses) on Sales of Other Real Estate	(1,296,000)		(10,860,000)
Fair Value, Measurements, Nonrecurring | OREO | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Real Estate Fair Value Disclosure	18,074,000		31,379,000
Fair Value, Measurements, Nonrecurring | Mortgage Servicing Rights
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gain (Loss) on Mortgage Servicing Rights	(230,000)		(6,191,000)
Fair Value, Measurements, Nonrecurring | Mortgage Servicing Rights | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Servicing Asset at Fair Value, Amount	32,420,000		23,102,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	1,513,157,000		2,547,876,000
Loans held for sale	465,983,000		223,638,000
Other assets	11,183,000		10,269,000
Assets, Fair Value Disclosure, Recurring	1,990,323,000		2,781,783,000
Other liabilities - derivatives	4,025,000		9,212,000
Total liabilities	19,467,000
Contingent Consideration Liability [Roll Forward]
Ending Balance	15,442,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring | MBS
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	1,308,838,000		2,320,934,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring | Municipal Bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	204,306,000		207,456,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Measurements, Recurring | Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	13,000		19,486,000
Fair Value, Inputs, Level 1 [Member] | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	331,550,000		491,228,000
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	331,550,000		491,228,000
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Nonrecurring | Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans receivable, net	0		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Nonrecurring | OREO
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Real Estate Fair Value Disclosure	0		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Nonrecurring | Mortgage Servicing Rights
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Servicing Asset at Fair Value, Amount	0		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	0		0
Loans held for sale	0		0
Other assets	0		0
Assets, Fair Value Disclosure, Recurring	0		0
Other liabilities - derivatives	0		0
Total liabilities	0
Contingent Consideration Liability [Roll Forward]
Ending Balance	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | MBS
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	0		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Municipal Bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	0		0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring | Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	0		0
Fair Value, Inputs, Level 2 [Member] | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	1,513,157,000		2,547,876,000
Held to maturity	206,000		1,747,000
Loans held for sale	465,983,000		273,957,000
Other assets	108,642,000	[1]	109,317,000	[1]
Non-maturity deposits	4,697,147,000		3,824,948,000
Deposits with stated maturities	1,738,970,000		2,660,870,000
Borrowings	1,437,491,000		1,706,662,000
Other liabilities	4,025,000		9,212,000
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	1,513,157,000		2,547,876,000
Held to maturity	206,000		1,747,000
Loans held for sale	465,983,000		273,957,000
Other assets	108,642,000	[1]	109,317,000	[1]
Non-maturity deposits	4,697,147,000		3,824,948,000
Deposits with stated maturities	1,768,818,000		2,710,740,000
Borrowings	1,457,911,000		1,724,347,000
Other liabilities	4,025,000		9,212,000
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Nonrecurring | Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans receivable, net	0		0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Nonrecurring | OREO
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Real Estate Fair Value Disclosure	0		0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Nonrecurring | Mortgage Servicing Rights
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Servicing Asset at Fair Value, Amount	0		0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	1,513,157,000		2,547,876,000
Loans held for sale			223,638,000
Loans Receivable Held-for-sale, Net	465,983,000
Other assets	11,183,000		10,269,000
Assets, Fair Value Disclosure, Recurring	1,990,323,000		2,781,783,000
Other liabilities - derivatives	4,025,000		9,212,000
Total liabilities	4,025,000
Contingent Consideration Liability [Roll Forward]
Ending Balance	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | MBS
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	1,308,838,000		2,320,934,000
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Municipal Bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	204,306,000		207,456,000
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring | Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	13,000		19,486,000
Fair Value, Inputs, Level 3 [Member] | Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans receivable, net	6,101,749,000		5,341,179,000
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value, Fair Value Disclosure [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans receivable, net	6,154,296,000		5,347,555,000
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring | Loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans receivable, net	172,172,000		268,837,000
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring | Loans | Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs, Selling Costs, Percent	4.50%
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring | Loans | Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs, Selling Costs, Percent	9.00%
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring | OREO
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other Real Estate Fair Value Disclosure	18,074,000		31,379,000
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring | OREO | Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs, Selling Costs, Percent	4.50%
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring | OREO | Maximum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Inputs, Selling Costs, Percent	9.00%
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring | Mortgage Servicing Rights
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Servicing Asset at Fair Value, Amount	32,420,000		23,102,000
Weighted average prepayment speed	18.30%
Weighted average discount rate	10.10%
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	0		0
Loans held for sale	0		0
Other assets	0		0
Assets, Fair Value Disclosure, Recurring	0		0
Other liabilities - derivatives	0		0
Total liabilities	15,442,000
Contingent Consideration Liability [Roll Forward]
Ending Balance	15,442,000
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | MBS
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	0		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Municipal Bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	0		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring | Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available for sale	$ 0		$ 0

[1] Other assets includes FHLB stock. As of December 31, 2012 and December 31, 2011, FHLB stock was carried at $97.5 million and $99.0 million, respectively