Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 item	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting.
Number of operating segments			4
Number of reportable segments			3
Number of rehabilitation hospitals			2
Revenues:
Rental income	$ 112,319	$ 113,756	$ 336,468	$ 329,191
Residents fees and services	74,946	42,352	224,634	113,906
Total revenues	187,265	156,108	561,102	443,097
Expenses:
Property operating expenses	74,729	46,805	222,893	125,109
Depreciation	38,473	35,276	114,472	102,673
General and administrative	7,798	8,352	24,615	24,106
Acquisition related costs	396	4,297	2,590	6,814
Impairment of assets			5,675	3,071
Total expenses	121,396	94,730	370,245	261,773
Operating income	65,869	61,378	190,857	181,324
Interest and other income	42	248	612	957
Interest expense	(29,405)	(30,417)	(88,536)	(87,426)
Loss on early extinguishment of debt	(692)	(6,349)	(797)	(6,349)
Loss on lease terminations		(104)		(104)
Gain (loss) on sale of properties	1,141	(101)	1,141	(101)
Equity in earnings of an investee	64	115	219	236
Income before income tax expense	37,019	24,770	103,496	88,537
Income tax expense	(125)	(43)	(405)	(290)
Income from continuing operations	36,894	24,727	103,091	88,247
Discontinued operations:
Income from discontinued operations	1,231	919	3,762	3,001
Impairment of assets from discontinued operations			(27,896)
Net income	38,125	25,646	78,957	91,248
Total assets	4,807,330	4,646,296	4,807,330	4,646,296	4,748,002
Triple Net Senior Living Communities
Revenues:
Rental income	57,073	60,496	170,794	178,964
Total revenues	57,073	60,496	170,794	178,964
Expenses:
Depreciation	16,760	17,433	50,696	51,816
Impairment of assets			4,371
Total expenses	16,760	17,433	55,067	51,816
Operating income	40,313	43,063	115,727	127,148
Interest expense	(6,546)	(8,665)	(20,030)	(29,073)
Loss on lease terminations		(104)		(104)
Gain (loss) on sale of properties	1,141		1,141
Income before income tax expense	34,908	34,294	96,838	97,971
Income from continuing operations	34,908	34,294	96,838	97,971
Discontinued operations:
Net income	34,908	34,294	96,838	97,971
Total assets	1,861,729	2,019,325	1,861,729	2,019,325
Managed Senior Living Communities
Revenues:
Residents fees and services	74,946	42,352	224,634	113,906
Total revenues	74,946	42,352	224,634	113,906
Expenses:
Property operating expenses	57,708	31,233	173,844	82,976
Depreciation	7,251	5,037	21,128	12,617
Total expenses	64,959	36,270	194,972	95,593
Operating income	9,987	6,082	29,662	18,313
Interest expense	(3,054)	(2,929)	(9,196)	(8,675)
Income before income tax expense	6,933	3,153	20,466	9,638
Income from continuing operations	6,933	3,153	20,466	9,638
Discontinued operations:
Net income	6,933	3,153	20,466	9,638
Total assets	967,187	803,009	967,187	803,009
MOBs
Revenues:
Rental income	50,910	48,821	152,492	136,910
Total revenues	50,910	48,821	152,492	136,910
Expenses:
Property operating expenses	17,021	15,572	49,049	42,133
Depreciation	13,514	11,858	39,804	35,396
Total expenses	30,535	27,430	88,853	77,529
Operating income	20,375	21,391	63,639	59,381
Interest expense	(1,369)	(1,014)	(4,103)	(1,807)
Gain (loss) on sale of properties		(101)		(101)
Income before income tax expense	19,006	20,276	59,536	57,473
Income from continuing operations	19,006	20,276	59,536	57,473
Discontinued operations:
Income from discontinued operations	1,231	919	3,762	3,001
Impairment of assets from discontinued operations			(27,896)
Net income	20,237	21,195	35,402	60,474
Total assets	1,732,217	1,625,180	1,732,217	1,625,180
All Other Operations
Revenues:
Rental income	4,336	4,439	13,182	13,317
Total revenues	4,336	4,439	13,182	13,317
Expenses:
Depreciation	948	948	2,844	2,844
General and administrative	7,798	8,352	24,615	24,106
Acquisition related costs	396	4,297	2,590	6,814
Impairment of assets			1,304	3,071
Total expenses	9,142	13,597	31,353	36,835
Operating income	(4,806)	(9,158)	(18,171)	(23,518)
Interest and other income	42	248	612	957
Interest expense	(18,436)	(17,809)	(55,207)	(47,871)
Loss on early extinguishment of debt	(692)	(6,349)	(797)	(6,349)
Equity in earnings of an investee	64	115	219	236
Income before income tax expense	(23,828)	(32,953)	(73,344)	(76,545)
Income tax expense	(125)	(43)	(405)	(290)
Income from continuing operations	(23,953)	(32,996)	(73,749)	(76,835)
Discontinued operations:
Net income	(23,953)	(32,996)	(73,749)	(76,835)
Total assets	$ 246,197	$ 198,782	$ 246,197	$ 198,782