Derivatives and Hedging Activities (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012		Mar. 31, 2012
Derivatives designated in hedge relationships
Derivative Asset, Fair Value	$ 58,563		$ 63,169		$ 60,115
Derivative Liability, Fair Value	71,933		77,906		80,174
Interest rate swaps [Member] | Designated as Hedging Instrument [Member]
Derivatives 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	145,382		161,133		220,630
Derivative Liability, Fair Value	$ 17,247	[2]	$ 19,080	[2]	$ 23,786	[2]

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

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