Senior Notes Payable and Other Debt (Details Textuals) (USD $)	1 Months Ended		3 Months Ended		9 Months Ended														1 Months Ended									1 Months Ended							9 Months Ended						1 Months Ended		9 Months Ended			1 Months Ended	9 Months Ended		9 Months Ended
	Oct. 31, 2011	Jun. 30, 2011	Sep. 30, 2011 Property State Year Province License LeaseRenewal	Mar. 31, 2011	Sep. 30, 2011 Segment Property Year State Province License LeaseRenewal	Sep. 30, 2010	Oct. 20, 2011	Dec. 31, 2010 Year Property	Dec. 31, 2009	Sep. 30, 2011 3 7/8 % Convertible Senior Notes due 2011 [Member]	Dec. 31, 2010 3 7/8 % Convertible Senior Notes due 2011 [Member]	Sep. 30, 2011 9% Senior Notes due 2012 [Member]	Dec. 31, 2010 9% Senior Notes due 2012 [Member]	Sep. 30, 2011 3.125% Senior Notes due 2015 [Member]	Dec. 31, 2010 3.125% Senior Notes due 2015 [Member]	Sep. 30, 2011 8 1/4% Senior Notes due 2012 [Member]	Sep. 30, 2011 6.25% Senior Notes due 2013 [Member]	Sep. 30, 2011 Nationwide Health Properties [Member] 6.90% Senior Notes due 2037 (Member)	Jul. 31, 2011 6 1/2% Senior Notes due 2016 [Member]	Sep. 30, 2011 6 1/2% Senior Notes due 2016 [Member]	Dec. 31, 2010 6 1/2% Senior Notes due 2016 [Member]	Sep. 30, 2011 Nationwide Health Properties [Member] 6.59% senior notes due 2038 [Member]	Sep. 30, 2011 6.90% Senior Notes due 2037 [Member]	Sep. 30, 2011 6.59% Senior Notes due 2038 [Member]	Sep. 30, 2011 6% Senior Notes due 2015 [Member]	Sep. 30, 2011 6 3/4% Senior Notes due 2017 [Member]	Dec. 31, 2010 6 3/4% Senior Notes due 2017 [Member]	Jul. 31, 2011 Nationwide Health Properties [Member] 6.50% senior notes due 2011 [Member]	May 31, 2011 4.750% Senior Notes due 2021 [Member]	Sep. 30, 2011 4.750% Senior Notes due 2021 [Member]	Sep. 30, 2011 Unsecured Revolving Credit Facilities [Member] 2012 maturities [Member]	Sep. 30, 2011 Nationwide Health Properties [Member] Unsecured Revolving Credit Facilities [Member] LIBOR plus 1.50% [Member]	Jul. 31, 2011 Nationwide Health Properties [Member] LIBOR plus 1.50% [Member]	Sep. 30, 2011 Nationwide Health Properties [Member] Alternate Base Rate plus 0.50% [Member]	Sep. 30, 2011 Nationwide Health Properties [Member] Senior Notes [Member]	Nov. 02, 2011 Unsecured term loan due 2012 [Member]	Sep. 30, 2011 Unsecured term loan due 2012 [Member]	Oct. 20, 2011 Letter of Credit [Member]	Oct. 20, 2011 Swingline Loans [Member]	Oct. 20, 2011 Loans In Alternative Currencies [Member]	Oct. 31, 2011 Minimum [Member] Unsecured Revolving Credit Facilities [Member]	Oct. 31, 2011 Maximum [Member] Unsecured Revolving Credit Facilities [Member]	Sep. 30, 2011 Unsecured Revolving Credit Facilities [Member]	Nov. 02, 2011 Unsecured Revolving Credit Facilities [Member]	Oct. 20, 2011 Unsecured Revolving Credit Facilities [Member]	Oct. 31, 2011 Nationwide Health Properties [Member] Senior unsecured term loan [Member]	Sep. 30, 2011 Nationwide Health Properties [Member] Senior unsecured term loan [Member]	May 31, 2011 Senior unsecured term loan [Member]	Sep. 30, 2011 Atria Senior Living Acquisition [Member]	Sep. 30, 2011 Nationwide Health Properties [Member] Property HousingCommunity	Jul. 31, 2011 Nationwide Health Properties [Member]
Debt Instrument [Line Items]
Portion of Credit Facility Interest Rate Based on Consolidated Leverage																															2.80%
Letters of Credit Outstanding on Credit Facility																																											$ 8,300,000
Unsecured revolving credit facilities available																																											517,700,000,000
Senior unsecured term loan																																															800,000,000	600,000,000
Outstanding senior unsecured term loan																																															250,000,000
Facility fee on unused commitments under term loan agreement					0.10%																																				0.15%	0.45%				0.25%
Line of credit facility repayment and termination date																																											Oct. 18, 2011
New unsecured credit facility maturity date																																											October 16, 2015
Balance outstanding of unsecured term loan																																					250,000,000							727,000,000			250,000,000
Line of credit facility optional extension period																																											1 year
Senior notes interest rate, Minimum																																			6.00%
Senior notes interest rate, Maximum																																			8.25%
Percentage of LIBOR										3.875%		9.00%		3.125%		8.25%	6.25%	6.90%		6.50%		6.59%	6.90%	6.59%	6.00%	6.75%				4.75%		1.69%	1.50%	0.50%											1.00%			5.00%
Mortgage debt in connection with acquisition		12,900,000																																															1,200,000,000	400,000,000
Aggregate principal amount of senior notes																		52,400,000				23,000,000							700,000,000																						991,600,000
Public Offering Price as a Percent of Par																													99.132%
Mortgage loans repaid in full					307,200,000
Loss on extinguishment of debt			8,685,000	16,500,000	25,211,000	6,549,000													8,700,000
Repayments of Senior Debt																			200,000,000									339,000,000
Early Repayment of Senior Debt																			206,500,000
Senior Note Redemption Price as a Percent of Par																			103.25%
No of housing communities owned																																																		8
Capital lease obligations			143,119,000		143,119,000
Proceeds from public offering																													693,900,000
Facility fee on unsecured revolving credit facilities																																											0.20%
LIBOR																																															LIBOR
Interest rate of term loan, maximum																																															1.69%
Interest rate of term loan, minimum																																															1.50%
Percentage of federal funds rate plus																																													0.50%
Percentage of euro currency rate loan																																													1.25%
Percentage of euro currency base rate loan																																													0.25%
Unsecured revolving credit facility outstanding																																												8,000,000
Unsecured revolving credit facility available																																				550,000,000	550,000,000							1,260,000,000
Aggregate borrowing capacity under the Unsecured Revolving Credit Facilities			1,000,000,000		1,000,000,000		2,500,000,000																															200,000,000	200,000,000	250,000,000
Senior Notes Payable and Other Debt (Textuals) [Abstract]
Aggregate borrowing capacity under the Unsecured Revolving Credit Facilities, Current							2,000,000,000
Unrestricted cash and cash equivalents			57,482,000		57,482,000	33,790,000		21,812,000	107,397,000
Net of Unrestricted Cash and Cash Equivalents and Unsecured Revolving Credit Facilities			416,500,000		416,500,000
Number of properties owned through consolidated joint ventures with mortgage debt			7		7			3
Percentage Of Line Of Credit Facility For Negotiated Rate Loans	50.00%
Joint venture partners' share of total debt			45,900,000		45,900,000			4,800,000
Line of credit			474,000,000,000		474,000,000,000			40,000,000
Debt related to investments in unconsolidated entities			131,700,000		131,700,000			45,900,000
Senior Notes										230,000,000	230,000,000	82,433,000	82,433,000	400,000,000	400,000,000	72,950,000	269,850,000			200,000,000	400,000,000		52,400,000	22,973,000	234,420,000	225,000,000	225,000,000			700,000,000
Net Assets held under capital leases			$ 226,900,000		$ 226,900,000			$ 0