Derivatives and Hedging Activities (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	$ 62,056	$ 47,764
Not Designated as Hedging Instrument [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,328,046	1,009,901
Derivative Asset, Fair Value	62,056	47,764
Derivative Liability, Notional/Contract Amount	1,016,204	837,961
Derivative Liability, Fair Value	60,217	44,274
Not Designated as Hedging Instrument [Member] | Interest rate swaps [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	976,823	774,623
Derivative Asset, Fair Value	58,875	44,270
Derivative Liability, Notional/Contract Amount	976,823	774,623
Derivative Liability, Fair Value	58,875	44,270
Not Designated as Hedging Instrument [Member] | Mortgage loan commitments [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	191,514	118,119
Derivative Asset, Fair Value	4,959	1,384
Derivative Liability, Notional/Contract Amount	0	0
Derivative Liability, Fair Value	0	0
Not Designated as Hedging Instrument [Member] | Forward sales contracts [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	159,377	113,426
Derivative Asset, Fair Value	(1,798)	2,106
Derivative Liability, Notional/Contract Amount	0	0
Derivative Liability, Fair Value	0	0
Not Designated as Hedging Instrument [Member] | Foreign exchange [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	332	3,733
Derivative Asset, Fair Value	20	4
Derivative Liability, Notional/Contract Amount	336	3,733
Derivative Liability, Fair Value	18	4
Not Designated as Hedging Instrument [Member] | Credit contracts [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	0	0
Derivative Asset, Fair Value	0	0
Derivative Liability, Notional/Contract Amount	17,951	44,983
Derivative Liability, Fair Value	0	0
Not Designated as Hedging Instrument [Member] | Other [Member]
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	0	0
Derivative Asset, Fair Value	0	0
Derivative Liability, Notional/Contract Amount	21,094	14,622
Derivative Liability, Fair Value	$ 1,324	$ 0