Derivative Instruments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Mar. 31, 2011 December 31, 2012 Swap 1 and 2 [Member] Swap [Member]	Jun. 30, 2012 December 31, 2012 - Swap 1 [Member] Swap [Member]	Dec. 31, 2011 December 31, 2012 - Swap 1 [Member] Swap [Member]	Jun. 30, 2012 December 31, 2012 - Swap 2 [Member] Swap [Member]	Dec. 31, 2011 December 31, 2012 - Swap 2 [Member] Swap [Member]	Jun. 30, 2012 May 9, 2016 [Member] Swap [Member]	Dec. 31, 2011 May 9, 2016 [Member] Swap [Member]	Jul. 31, 2011 May 9, 2016 [Member] Swap [Member]
Derivative [Line Items]
Stated Interest Rate						3.105%	3.105%	3.105%	3.105%	2.02%	2.02%
Pre-tax charge on derivative instruments	$ 202	$ 376	$ 662	$ (3,556)	$ 3,900
Notional Amount						55,250	59,500	32,500	35,000	74,063	75,000	75,000
Market Value (Liability)						$ (732)	$ (1,394)	$ (430)	$ (820)	$ (3,200)	$ (2,810)