Derivatives and Hedging Activities (Not Designated as Hedging Instruments, Notional Values, Contractual Amounts and Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	$ 76,196	$ 55,197	$ 43,097
Derivative Liability, Fair Value	67,936	55,439	49,280
Not Designated as Hedging Instrument
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,788,645	1,807,942	1,858,254
Derivative Asset, Fair Value	63,586	49,941	43,097
Derivative Liability, Notional/Contract Amount	1,887,734	1,821,674	1,826,094
Derivative Liability, Fair Value	63,358	48,756	41,696
Not Designated as Hedging Instrument | Interest rate swaps
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,745,769	1,673,012	1,655,371
Derivative Asset, Fair Value	63,171	48,366	40,937
Derivative Liability, Notional/Contract Amount	1,745,769	1,673,012	1,655,371
Derivative Liability, Fair Value	63,171	48,366	40,937
Not Designated as Hedging Instrument | Mortgage loan commitments
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	30,500	102,523	167,634
Derivative Asset, Fair Value	279	1,408	1,975
Derivative Liability, Notional/Contract Amount	0	0	0
Derivative Liability, Fair Value	0	0	0
Not Designated as Hedging Instrument | Forward sales contracts
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	0	0	0
Derivative Asset, Fair Value		0	0
Derivative Liability, Notional/Contract Amount	12,896	47,657	67,528
Derivative Liability, Fair Value	75	272	91
Not Designated as Hedging Instrument | Credit Risk Contract
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	0	10,001	20,504
Derivative Asset, Fair Value	0	0	0
Derivative Liability, Notional/Contract Amount	84,219	69,227	58,157
Derivative Liability, Fair Value	0	0	0
Not Designated as Hedging Instrument | Equity Swap
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	0	0	0
Derivative Asset, Fair Value	0	0	0
Derivative Liability, Notional/Contract Amount	32,904	25,198	30,964
Derivative Liability, Fair Value		0	515
Not Designated as Hedging Instrument | Foreign Exchange
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	12,376	22,406	14,745
Derivative Asset, Fair Value	136	167	185
Derivative Liability, Notional/Contract Amount	11,946	6,580	14,074
Derivative Liability, Fair Value	112	118	153
Level 2
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	76,196	55,197	43,097
Derivative Liability, Fair Value	67,936	55,439	48,765
Level 2 | Not Designated as Hedging Instrument | Interest rate swaps
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	63,171	48,366	40,937
Derivative Liability, Fair Value	63,171	48,366	40,937
Level 2 | Not Designated as Hedging Instrument | Mortgage loan commitments
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	279	1,408	1,975
Level 2 | Not Designated as Hedging Instrument | Forward sales contracts
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	0	0	0
Derivative Liability, Fair Value	75	272	91
Level 2 | Not Designated as Hedging Instrument | Equity Swap
Derivatives not designated in hedge relationships
Derivative Liability, Fair Value			0
Level 2 | Not Designated as Hedging Instrument | Foreign Exchange
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	136	167	185
Derivative Liability, Fair Value	112	118	153
Level 3
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	0	0	0
Derivative Liability, Fair Value	0	0	515
Level 3 | Not Designated as Hedging Instrument | Interest rate swaps
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	0	0	0
Derivative Liability, Fair Value	0	0	0
Level 3 | Not Designated as Hedging Instrument | Mortgage loan commitments
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	0	0	0
Level 3 | Not Designated as Hedging Instrument | Forward sales contracts
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value		0	0
Derivative Liability, Fair Value	0	0	0
Level 3 | Not Designated as Hedging Instrument | Equity Swap
Derivatives not designated in hedge relationships
Derivative Liability, Fair Value	0		515
Level 3 | Not Designated as Hedging Instrument | Foreign Exchange
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	0	0	0
Derivative Liability, Fair Value	$ 0	$ 0	$ 0