Significant Tenant (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Operations
Total revenues	$ 146,972	$ 101,162	$ 292,045	$ 199,714
Operating income	61,111	53,318	122,029	107,641
Net income	33,251	51,048	65,603	82,823
Cash Flows
Cash provided by operating activities			146,529	131,731
Change in cash and cash equivalents			(3,155)	17,216
Cash and cash equivalents at beginning of period			23,560	10,866
Cash and cash equivalents at end of period	20,405	28,082	20,405	28,082
Rents from significant lessee | Five Star
Operations
Total revenues	349,094	311,884	695,215	619,500
Operating income	6,611	8,072	9,124	14,531
Income from continuing operations	4,931	5,987	5,677	11,896
Net income	4,638	5,196	5,007	9,329
Cash Flows
Cash provided by operating activities			30,748	31,445
Net cash used in discontinued operations			(316)	(2,365)
Cash used in investing activities			(22,057)	(69,354)
Cash (used in) provided by financing activities			(13,114)	62,662
Change in cash and cash equivalents			(4,739)	22,388
Cash and cash equivalents at beginning of period			28,374	20,770
Cash and cash equivalents at end of period	23,635	43,158	23,635	43,158
Financial Position
Current assets	138,739	160,156	138,739	160,156
Non-current assets	442,946	321,395	442,946	321,395
Total indebtedness	109,226	73,975	109,226	73,975
Current liabilities	195,735	160,174	195,735	160,174
Non-current liabilities	99,981	91,748	99,981	91,748
Total shareholders' equity	$ 285,969	$ 229,629	$ 285,969	$ 229,629