Derivative Instruments not Designated as Hedging Instruments (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013		Jun. 30, 2013
Derivatives not designated in hedge relationships
Derivative Asset, Fair Value	$ 50,550		$ 47,902		$ 53,158
Derivative Liability, Fair Value	57,544		58,201		62,217
Not Designated as Hedging Instrument
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,828,587		1,760,450		1,901,310
Derivative Asset, Fair Value	50,550	[1]	47,902	[1]	53,158	[1]
Derivative Liability, Notional/Contract Amount	1,818,894		1,743,151		1,612,438
Derivative Liability, Fair Value	48,555		46,627		47,898
Not Designated as Hedging Instrument | Interest rate swaps
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	1,618,463		1,622,525		1,502,079
Derivative Asset, Fair Value	47,952	[1]	46,577	[1]	47,804	[1]
Derivative Liability, Notional/Contract Amount	1,618,463		1,622,531		1,502,079
Derivative Liability, Fair Value	47,952		46,577		47,804
Not Designated as Hedging Instrument | Mortgage loan commitments
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	169,232		90,541		251,198
Derivative Asset, Fair Value	2,491	[1]	891	[1]	779	[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	0		40,906		139,093
Derivative Asset, Fair Value	0	[1]	384	[1]	4,458	[1]
Derivative Liability, Notional/Contract Amount	80,161		0		0
Derivative Liability, Fair Value	545		0		0
Not Designated as Hedging Instrument | Credit Risk Contract
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	15,269		0		0
Derivative Asset, Fair Value	0	[1]	0	[1]	0	[1]
Derivative Liability, Notional/Contract Amount	52,319		49,914		50,754
Derivative Liability, Fair Value	10		0		0
Not Designated as Hedging Instrument | Foreign Exchange
Derivatives not designated in hedge relationships
Derivative Asset, Notional/Contract Amount	25,623		6,478		8,940
Derivative Asset, Fair Value	107	[1]	50	[1]	117	[1]
Derivative Liability, Notional/Contract Amount	7,568		6,893		7,235
Derivative Liability, Fair Value	48		50		94
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	[1]	0	[1]	0	[1]
Derivative Liability, Notional/Contract Amount	60,383		63,813		52,370
Derivative Liability, Fair Value	$ 0		$ 0		$ 0

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