Derivative Instruments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2011 December 31, 2012 Swap 1 and 2 [Member] Swap [Member]	Sep. 30, 2012 December 31, 2012 - Swap 1 [Member] Swap [Member]	Dec. 31, 2011 December 31, 2012 - Swap 1 [Member] Swap [Member]	Sep. 30, 2012 December 31, 2012 - Swap 2 [Member] Swap [Member]	Dec. 31, 2011 December 31, 2012 - Swap 2 [Member] Swap [Member]	Sep. 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	$ 294	$ (1,881)	$ 956	$ (5,437)	$ 3,900
Notional Amount						53,125	59,500	31,250	35,000	73,125	75,000	75,000
Market Value (Liability)						$ (380)	$ (1,394)	$ (224)	$ (820)	$ (3,464)	$ (2,810)