SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Real Estate
Beginning balance	$ 615,666	$ 519,460	$ 502,617
Acquisitions	106,135	94,250	13,000
Improvements	3,230	5,941	3,843
Conversion of mortgage loans into owned properties		2,900
Cost of real estate sold		(6,885)
Ending balance	725,031	615,666	519,460
Accumulated depreciation
Beginning balance	158,709	145,180	130,475
Depreciation expense	19,487	16,016	14,705
Cost of real estate sold		(2,487)
Ending balance	$ 178,196	$ 158,709	$ 145,180