Derivative Instruments (Narrative) (Details) (USD $)	12 Months Ended						12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 NAB Australian Corporate Credit Facility [Member]	Oct. 31, 2012 US GE Capital Term Loan [Member]	Dec. 31, 2011 US GE Capital Term Loan [Member]	Dec. 31, 2012 US Bank Of America Revolver [Member]
Derivative [Line Items]
Minimum swap percentage				75.00%
Interest rate swap term				5 years
Percentage of variable interest debt converted to fixed rate				100.00%
Swap contract rate				5.50%			1.44%
Interest rate swap, amount in-the-money				$ 160,000
Increase (decrease) in derivative fixed interest rate				(0.05%)			0.10%
Note payable	196,597,000	209,614,000			27,700,000	32,188,000	30,000,000
Interest rate swap	5,855,000	4,722,000					29,100,000
Fixed interest rate				8.15%			5.84%
Fixed interest rate margin				2.65%			4.50%
Interest rate				5.82%			3.21%
Increase (decrease) in interest expense from derivatives	$ 1,100,000	$ 5,000,000	$ (284,000)