Derivative Financial Instruments (Details) (USD $)	3 Months Ended
	Mar. 31, 2012 swaps	Mar. 31, 2011	Dec. 31, 2011
Derivative [Line Items]
Number of derivative instruments obtained	6
Term of derivative instruments (in years)	7
Amount of borrowings outstanding	$ 225,000,000
Interest rate under derivative instruments	1.678%
Expected increase to interest expense	3,100,000
Derivatives designated as cash flow hedges in other liabilities [Abstract]
Interest rate swaps	1,098,000		2,202,000
Amount of unrealized gain recognized in AOCL on derivatives (effective portion) [Abstract]
Interest rate swaps	1,104,000	0
Amount of (gain) reclassified out of AOCL into contractual interest expense (effective portion) [Abstract]
Interest rate swaps	$ (33,000)	$ (29,000)