Derivatives (Offsetting Derivatives Assets) (Details) (Interest Rate Swap [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Interest Rate Swap [Member]
Derivative Assets
Derivative Assets, Gross Amounts of Recognized Assets	$ 19,663	$ 22,213
Derivative Assets, Gross Amounts Offset in the Statement of Financial Position	0	0
Derivatives Assets, Net Amounts of Assets presented in the Statement of Financial Position	19,663	22,213
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross Amounts Not Offset in the Statement of Financial Position, Financial Instruments	(15)	(16)
Derivative Assets, Gross Amounts Not Offset in the Statement of Financial Position, Collateral Posted	0	0
Derivative Assets, Net Amount	$ 19,648	$ 22,197