Fair Value Measurement (Recurring and Nonrecurring Table) (Details) - USD ($) $ in Thousands		3 Months Ended				12 Months Ended
		Jun. 30, 2015		Jun. 30, 2014		Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
True-up Liabitlity Discount Rate		3.58%		3.12%
True-up Liability Effect of Change in Discount Rate By One Percent		$ 600		$ (700)
Collateral Dependant Impaired and Non Accrual Loans Carrying Amount		72,600		56,000		$ 56,000
Recurring Fair Value Measurements
Available-for-sale		3,838,509		3,478,420		3,545,288
Residential loans held for sale		8,302		21,632		14,389
Derivative Asset, Fair Value, Gross Asset		48,073		50,550		55,197
Total Assets, Fair Value Disclosure, Recurring		3,894,884		3,550,602		3,614,874
Derivative Liability, Fair Value, Gross Liability		51,497		57,544		55,439
True Up Liability		13,408		12,581		13,294
Total liabilities at fair value on a recurring basis		64,905	[1]	70,125		68,733	[1]
Nonrecurring Fair Value Measurements [Abstract]
Fair Value of Mortgage Servicing Rights		20,809	[2]	21,987		21,228	[2]
Impaired and Non Accrual Loans Fair Value Disclosure		72,580	[3]	56,006		56,041	[3]
Other Real Estate, Non Covered		33,078	[4]	17,052		12,510	[4]
Other Real Estate Covered by Loss Share		4	[5]	22,782		3,614	[5]
Nonrecurring Fair Value		126,471		117,827		93,393
Impairment of Noncovered Other Real Estate Owned				700		2,600
Impairment of Covered Other Real Esate Owned				700		1,200
Foreclosed Real Estate Expense		2,100
Level 1
Recurring Fair Value Measurements
Available-for-sale		2,824		2,935		2,974
Residential loans held for sale		0		0		0
Derivative Asset, Fair Value, Gross Asset		0		0		0
Total Assets, Fair Value Disclosure, Recurring		2,824		2,935		2,974
Derivative Liability, Fair Value, Gross Liability		0		0		0
True Up Liability		0		0		0
Total liabilities at fair value on a recurring basis		0	[1]	0		0	[1]
Nonrecurring Fair Value Measurements [Abstract]
Fair Value of Mortgage Servicing Rights		0	[2]	0		0	[2]
Impaired and Non Accrual Loans Fair Value Disclosure		0	[3]	0		0	[3]
Other Real Estate, Non Covered		0	[4]	0		0	[4]
Other Real Estate Covered by Loss Share		0	[5]	0		0	[5]
Nonrecurring Fair Value		0		0		0
Level 2
Recurring Fair Value Measurements
Available-for-sale		3,524,149		3,124,752		3,203,127
Residential loans held for sale		8,302		21,632		14,389
Derivative Asset, Fair Value, Gross Asset		48,073		50,550		55,197
Total Assets, Fair Value Disclosure, Recurring		3,580,524		3,196,934		3,272,713
Derivative Liability, Fair Value, Gross Liability		51,497		57,544		55,439
True Up Liability		0		0		0
Total liabilities at fair value on a recurring basis		51,497	[1]	57,544		55,439	[1]
Nonrecurring Fair Value Measurements [Abstract]
Fair Value of Mortgage Servicing Rights		0	[2]	0		0	[2]
Impaired and Non Accrual Loans Fair Value Disclosure		0	[3]	0		0	[3]
Other Real Estate, Non Covered		0	[4]	0		0	[4]
Other Real Estate Covered by Loss Share		0	[5]	0		0	[5]
Nonrecurring Fair Value		0		0		0
Level 3
Recurring Fair Value Measurements
Available-for-sale		311,536		350,733		339,187
Residential loans held for sale		0		0		0
Derivative Asset, Fair Value, Gross Asset		0		0		0
Total Assets, Fair Value Disclosure, Recurring		311,536		350,733		339,187
Derivative Liability, Fair Value, Gross Liability		0		0		0
True Up Liability		13,408		12,581		13,294
Total liabilities at fair value on a recurring basis		13,408	[1]	12,581		13,294	[1]
Nonrecurring Fair Value Measurements [Abstract]
Fair Value of Mortgage Servicing Rights		20,809		21,987		21,228
Impaired and Non Accrual Loans Fair Value Disclosure		72,580		56,006		56,041
Other Real Estate, Non Covered		33,078		17,052		12,510	[4]
Other Real Estate Covered by Loss Share		4		22,782		3,614	[5]
Nonrecurring Fair Value		126,471		117,827		93,393
US Treasury Securities
Recurring Fair Value Measurements
Available-for-sale		5,005
US Treasury Securities | Level 2
Recurring Fair Value Measurements
Available-for-sale		5,005
Equity Securities
Recurring Fair Value Measurements
Available-for-sale		2,824		2,935		2,974
Equity Securities | Level 1
Recurring Fair Value Measurements
Available-for-sale		2,824		2,935		2,974
Equity Securities | Level 2
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Equity Securities | Level 3
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Non-marketable Equity Securities
Recurring Fair Value Measurements
Available-for-sale				3,281
Non-marketable Equity Securities | Level 2
Recurring Fair Value Measurements
Available-for-sale				10
Non-marketable Equity Securities | Level 3
Recurring Fair Value Measurements
Available-for-sale				3,271
US Government Agencies Debt Securities
Recurring Fair Value Measurements
Available-for-sale		2,510				2,482
US Government Agencies Debt Securities | Level 2
Recurring Fair Value Measurements
Available-for-sale		2,510
U.S. States and political subdivisions debt securities
Recurring Fair Value Measurements
Available-for-sale		207,617		240,805		227,342
U.S. States and political subdivisions debt securities | Level 1
Recurring Fair Value Measurements
Available-for-sale		0		0		0
U.S. States and political subdivisions debt securities | Level 2
Recurring Fair Value Measurements
Available-for-sale		207,617		240,805		227,342
U.S. States and political subdivisions debt securities | Level 3
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises
Recurring Fair Value Measurements
Available-for-sale		960,852		1,018,174		970,998
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises | Level 1
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises | Level 2
Recurring Fair Value Measurements
Available-for-sale		960,852		1,018,174		970,998
Residential Mortgage Backed Securities Issued by US Government Sponsored Enterprises | Level 3
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Commercial Mortgage Backed Securities Issued by US Government Sponsored Enterprises
Recurring Fair Value Measurements
Available-for-sale		170,338		85,698		103,403
Commercial Mortgage Backed Securities Issued by US Government Sponsored Enterprises | Level 1
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Commercial Mortgage Backed Securities Issued by US Government Sponsored Enterprises | Level 2
Recurring Fair Value Measurements
Available-for-sale		170,338		85,698		103,403
Commercial Mortgage Backed Securities Issued by US Government Sponsored Enterprises | Level 3
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Residential Collateralized Mortgage-Backed Securities Issued by US Government Sponsored Enterprises
Recurring Fair Value Measurements
Available-for-sale		1,949,389		1,598,031		1,676,567
Residential Collateralized Mortgage-Backed Securities Issued by US Government Sponsored Enterprises | Level 1
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Residential Collateralized Mortgage-Backed Securities Issued by US Government Sponsored Enterprises | Level 2
Recurring Fair Value Measurements
Available-for-sale		1,949,389		1,598,031		1,676,567
Residential Collateralized Mortgage-Backed Securities Issued by US Government Sponsored Enterprises | Level 3
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Residential Collateralized Mortgage-Backed Securities Issued by Non-US Government Agency
Recurring Fair Value Measurements
Available-for-sale		5		8		7
Residential Collateralized Mortgage-Backed Securities Issued by Non-US Government Agency | Level 1
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Residential Collateralized Mortgage-Backed Securities Issued by Non-US Government Agency | Level 2
Recurring Fair Value Measurements
Available-for-sale		0		1		1
Residential Collateralized Mortgage-Backed Securities Issued by Non-US Government Agency | Level 3
Recurring Fair Value Measurements
Available-for-sale		5		7		6
Commercial Collateralized Mortgage Backed Securities Issued by US Government Sponsored Enterprises
Recurring Fair Value Measurements
Available-for-sale		228,438		182,033		222,334
Commercial Collateralized Mortgage Backed Securities Issued by US Government Sponsored Enterprises | Level 1
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Commercial Collateralized Mortgage Backed Securities Issued by US Government Sponsored Enterprises | Level 2
Recurring Fair Value Measurements
Available-for-sale		228,438		182,033		222,334
Commercial Collateralized Mortgage Backed Securities Issued by US Government Sponsored Enterprises | Level 3
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Corporate debt securities
Recurring Fair Value Measurements
Available-for-sale		53,450		53,490		51,337
Corporate debt securities | Level 1
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Corporate debt securities | Level 2
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Corporate debt securities | Level 3
Recurring Fair Value Measurements
Available-for-sale				53,490		51,337
Collateralized Loan Obligations
Recurring Fair Value Measurements
Available-for-sale		258,081		293,965		287,844
Collateralized Loan Obligations | Level 1
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Collateralized Loan Obligations | Level 2
Recurring Fair Value Measurements
Available-for-sale		0		0		0
Collateralized Loan Obligations | Level 3
Recurring Fair Value Measurements
Available-for-sale				293,965		287,844
Not Designated as Hedging Instrument
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset	[6]	46,920		50,550		49,941
Derivative Liability, Fair Value, Gross Liability		46,393		48,555		48,756
Interest Rate Swap | Designated as Hedging Instrument
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		1,153		0	[6]	5,256	[6]
Derivative Liability, Fair Value, Gross Liability		5,104		8,989		6,683
Interest Rate Swap | Designated as Hedging Instrument | Level 1
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		0		0		0
Derivative Liability, Fair Value, Gross Liability		0		0		0
Interest Rate Swap | Designated as Hedging Instrument | Level 2
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		1,153		0		5,256
Derivative Liability, Fair Value, Gross Liability		5,104		8,989		6,683
Interest Rate Swap | Designated as Hedging Instrument | Level 3
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		0		0		0
Derivative Liability, Fair Value, Gross Liability		0		0		0
Interest Rate Swap | Not Designated as Hedging Instrument
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		46,216		47,952	[6]	48,366	[6]
Derivative Liability, Fair Value, Gross Liability		46,216		47,952		48,366
Interest Rate Swap | Not Designated as Hedging Instrument | Level 1
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		0		0		0
Derivative Liability, Fair Value, Gross Liability		0		0		0
Interest Rate Swap | Not Designated as Hedging Instrument | Level 2
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		46,216		47,952		48,366
Derivative Liability, Fair Value, Gross Liability		46,216		47,952		48,366
Interest Rate Swap | Not Designated as Hedging Instrument | Level 3
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		0		0		0
Derivative Liability, Fair Value, Gross Liability		0		0		0
Mortgage Loan Commitments | Not Designated as Hedging Instrument
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		342		2,491	[6]	1,408	[6]
Derivative Liability, Fair Value, Gross Liability		0		0		0
Mortgage Loan Commitments | Not Designated as Hedging Instrument | Level 1
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		0		0		0
Mortgage Loan Commitments | Not Designated as Hedging Instrument | Level 2
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		342		2,491		1,408
Mortgage Loan Commitments | Not Designated as Hedging Instrument | Level 3
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		0		0		0
Forward sales contracts | Not Designated as Hedging Instrument
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		106		0	[6]	0	[6]
Derivative Liability, Fair Value, Gross Liability		0		545		272
Forward sales contracts | Not Designated as Hedging Instrument | Level 1
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		0		0		0
Derivative Liability, Fair Value, Gross Liability		0		0		0
Forward sales contracts | Not Designated as Hedging Instrument | Level 2
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		106		0		0
Derivative Liability, Fair Value, Gross Liability		0		545		272
Forward sales contracts | Not Designated as Hedging Instrument | Level 3
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		0		0		0
Derivative Liability, Fair Value, Gross Liability		0		0		0
Foreign Exchange | Not Designated as Hedging Instrument
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		256		107	[6]	167	[6]
Derivative Liability, Fair Value, Gross Liability		177		48		118
Foreign Exchange | Not Designated as Hedging Instrument | Level 1
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		0		0		0
Derivative Liability, Fair Value, Gross Liability		0		0		0
Foreign Exchange | Not Designated as Hedging Instrument | Level 2
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		256		107		167
Derivative Liability, Fair Value, Gross Liability		177		48		118
Foreign Exchange | Not Designated as Hedging Instrument | Level 3
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset		0		0		0
Derivative Liability, Fair Value, Gross Liability		0		0		0
Equity Swap | Not Designated as Hedging Instrument
Recurring Fair Value Measurements
Derivative Liability, Fair Value, Gross Liability		0
Equity Swap | Not Designated as Hedging Instrument | Level 1
Recurring Fair Value Measurements
Derivative Liability, Fair Value, Gross Liability		0
Equity Swap | Not Designated as Hedging Instrument | Level 3
Recurring Fair Value Measurements
Derivative Liability, Fair Value, Gross Liability		0
Credit Risk Contract | Not Designated as Hedging Instrument
Recurring Fair Value Measurements
Derivative Asset, Fair Value, Gross Asset	[6]	$ 0		0		0
Derivative Liability, Fair Value, Gross Liability				10		$ 0
Credit Risk Contract | Not Designated as Hedging Instrument | Level 1
Recurring Fair Value Measurements
Derivative Liability, Fair Value, Gross Liability				0
Credit Risk Contract | Not Designated as Hedging Instrument | Level 2
Recurring Fair Value Measurements
Derivative Liability, Fair Value, Gross Liability				10
Credit Risk Contract | Not Designated as Hedging Instrument | Level 3
Recurring Fair Value Measurements
Derivative Liability, Fair Value, Gross Liability				$ 0

[1] (1) There were no transfers between levels 1, 2 or 3 of the fair value hierarchy during the three months ended June 30, 2015.

[2] (2) MSRs with a recorded investment of $20.6 million were reduced by a specific valuation allowance totaling $0.5 million to a reported carrying value of $20.1 million resulting in recognition of $0.6 million in recoveries included in loan sales and servicing income in the three months ended June 30, 2015.

[3] (3) Collateral dependent impaired loans with a recorded investment of $82.7 million were reduced by specific valuation allowance allocations totaling $10.2 million to a reported net carrying value of $72.6 million.

[4] (4) Amounts do not include assets held at cost at June 30, 2015. During the three months ended June 30, 2015, the re-measurement of foreclosed assets at fair value subsequent to initial recognition resulted in losses of $2.1 million included in noninterest expense.

[5] (5) Amounts do not include assets held at cost at June 30, 2015. During the three months ended June 30, 2015, the re-measurement of covered foreclosed assets at fair value subsequent to initial recognition was immaterial.

[6] (1) Included in "Other assets" on the Consolidated Balance Sheets(2) Included in "Other liabilities" on the Consolidated Balance Sheets