Derivatives and Hedging Activities (Not Designated as Hedging Instruments, Notional Values, Contractual Amounts and Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	$ 98,549	$ 58,107	$ 72,573
Derivative Liability, Fair Value	78,621	52,745	65,447
Not Designated as Hedging Instrument
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,906,785	1,858,882	1,811,324
Derivative Asset, Fair Value	75,831	49,368	59,885
Derivative Liability, Notional/Contract Amount	1,977,022	1,956,287	1,851,603
Derivative Liability, Fair Value	75,383	49,209	59,384
Not Designated as Hedging Instrument | Interest rate swaps
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,850,414	1,824,576	1,718,850
Derivative Asset, Fair Value	75,139	48,920	59,147
Derivative Liability, Notional/Contract Amount	1,850,414	1,824,576	1,718,850
Derivative Liability, Fair Value	75,139	48,920	59,147
Not Designated as Hedging Instrument | Mortgage loan commitments
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	40,904	20,635	51,937
Derivative Asset, Fair Value	240	149	388
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
Derivative Asset, Fair Value		0	0
Derivative Liability, Notional/Contract Amount	$ 7,527	9,659	11,758
Derivative Liability, Fair Value	82	5	68
Not Designated as Hedging Instrument | Credit Risk Contract
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	74,315	73,715	80,047
Derivative Liability, Fair Value	8	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	36,125	36,631	30,896
Derivative Liability, Fair Value	0	0	0
Not Designated as Hedging Instrument | Foreign Exchange
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	15,467	13,671	40,537
Derivative Asset, Fair Value	452	299	350
Derivative Liability, Notional/Contract Amount	8,641	11,706	10,052
Derivative Liability, Fair Value	154	284	169
Level 2
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	98,549	58,107	72,573
Derivative Liability, Fair Value	$ 78,621	52,745	65,447
Level 2 | Not Designated as Hedging Instrument
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value
Level 2 | Not Designated as Hedging Instrument | Interest rate swaps
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	$ 75,139	48,920	59,147
Derivative Liability, Fair Value	75,139	48,920	59,147
Level 2 | Not Designated as Hedging Instrument | Mortgage loan commitments
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	240	149	388
Level 2 | Not Designated as Hedging Instrument | Forward sales contracts
Derivatives not designated in hedge relationships
Derivative Liability, Fair Value	82	5	68
Level 2 | Not Designated as Hedging Instrument | Foreign Exchange
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	452	299	350
Derivative Liability, Fair Value	$ 154	$ 284	$ 169