Derivatives and Hedging Activities (Not Designated as Hedging Instruments, Notional Values, Contractual Amounts and Fair Value) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	$ 72,573,000		$ 55,197,000		$ 46,467,000
Derivative Liability, Fair Value	65,447,000		55,439,000		55,106,000
Not Designated as Hedging Instrument
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,823,082,000		1,855,599,000		1,806,773,000
Derivative Asset, Fair Value	59,885,000	[1]	49,941,000	[1]	46,466,000	[1]
Derivative Liability, Notional/Contract Amount	1,839,845,000		1,823,957,000		1,730,338,000
Derivative Liability, Fair Value	59,384,000		48,756,000		44,714,000
Not Designated as Hedging Instrument | Interest rate swaps
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,718,850,000		1,673,012,000		1,603,125,000
Derivative Asset, Fair Value	59,147,000		48,366,000	[1]	44,672,000	[1]
Derivative Liability, Notional/Contract Amount	1,718,850,000		1,673,012,000		1,603,125,000
Derivative Liability, Fair Value	59,147,000		48,366,000		44,672,000
Not Designated as Hedging Instrument | Mortgage loan commitments
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	51,937,000		102,523,000		132,614,000
Derivative Asset, Fair Value	388,000		1,408,000	[1]	1,575,000	[1]
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	11,757,927		47,657,000		53,404,000
Derivative Asset, Fair Value			0	[1]	167,000	[1]
Derivative Liability, Notional/Contract Amount	0		0		0
Derivative Liability, Fair Value	68,000		272,000		0
Not Designated as Hedging Instrument | Credit Risk Contract
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	0		10,001,000		0
Derivative Asset, Fair Value	0	[1]	0	[1]	0	[1]
Derivative Liability, Notional/Contract Amount	80,047,000		69,227,000		49,456,000
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	40,537,000		22,406,000		17,630,000
Derivative Asset, Fair Value	350,000		167,000	[1]	52,000	[1]
Derivative Liability, Notional/Contract Amount	10,052,000		6,580,000		15,898,000
Derivative Liability, Fair Value	169,000		118,000		42,000
Not Designated as Hedging Instrument | Other Contract
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	0		0		0
Derivative Asset, Fair Value	0		0	[1]	0	[1]
Derivative Liability, Notional/Contract Amount	30,896,000		75,138,000		61,859,000
Derivative Liability, Fair Value	$ 0		$ 0		$ 0

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