Derivatives and Hedging Activities (Details 1) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012		Mar. 31, 2012
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	$ 58,563		$ 63,169		$ 60,115
Derivative Liability, Fair Value	71,933		77,906		80,174
Not Designated as Hedging Instrument [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,612,262		1,503,785		1,473,685
Derivative Asset, Fair Value	58,563	[1]	63,169	[1]	60,115	[1]
Derivative Liability, Notional/Contract Amount	1,350,738		1,267,578		1,066,990
Derivative Liability, Fair Value	54,686	[2]	58,826	[2]	56,388	[2]
Not Designated as Hedging Instrument [Member] | Interest rate swaps [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,266,831		1,204,835		1,016,626
Derivative Asset, Fair Value	54,590	[1]	58,769	[1]	56,298	[1]
Derivative Liability, Notional/Contract Amount	1,266,831		1,204,835		1,016,626
Derivative Liability, Fair Value	54,590	[2]	58,769	[2]	56,298	[2]
Not Designated as Hedging Instrument [Member] | Mortgage loan commitments [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	214,573		168,271		247,453
Derivative Asset, Fair Value	4,152	[1]	4,400	[1]	3,268	[1]
Derivative Liability, Notional/Contract Amount	0		0		0
Derivative Liability, Fair Value	0	[2]	0	[2]	0	[2]
Not Designated as Hedging Instrument [Member] | Forward sales contracts [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	122,795		124,017		201,637
Derivative Asset, Fair Value	(284)	[1]	(62)	[1]	446	[1]
Derivative Liability, Notional/Contract Amount	0		0		0
Derivative Liability, Fair Value	0	[2]	0	[2]	0	[2]
Not Designated as Hedging Instrument [Member] | Foreign exchange [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	8,063		6,662		7,969
Derivative Asset, Fair Value	105	[1]	62	[1]	103	[1]
Derivative Liability, Notional/Contract Amount	8,080		6,026		8,043
Derivative Liability, Fair Value	96	[2]	57	[2]	90	[2]
Not Designated as Hedging Instrument [Member] | Credit contracts [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	0		0		0
Derivative Asset, Fair Value	0	[1]	0	[1]	0	[1]
Derivative Liability, Notional/Contract Amount	40,541		25,225		17,805
Derivative Liability, Fair Value	0	[2]	0	[2]	0	[2]
Not Designated as Hedging Instrument [Member] | Other [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	0		0		0
Derivative Asset, Fair Value	0	[1]	0	[1]	0	[1]
Derivative Liability, Notional/Contract Amount	35,286		31,492		24,516
Derivative Liability, Fair Value	$ 0	[2]	$ 0	[2]	$ 0	[2]

[1] (a) Included in Other Assets on the Consolidated Balance Sheet

[2] (b) Included in Other Liabilities on the Consolidated Balance Sheet