Senior Notes Payable and Other Debt - Senior Notes (Details) $ in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 CAD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2021 CAD ($)	Nov. 30, 2021 CAD ($)	Aug. 31, 2021 USD ($)	Jul. 31, 2021 USD ($)	Feb. 28, 2021 USD ($)	Oct. 30, 2020 USD ($)	Aug. 31, 2020 USD ($)
Debt Instrument [Line Items]
Loss on extinguishment of debt, net		$ 59,299		$ 10,791	$ 41,900
Long-term debt, gross		$ 12,093,138		11,983,071
6.90% Senior Notes Due 2037
Debt Instrument [Line Items]
Interest rate		6.90%				6.90%
Six Point Five Nine Percent Senior Notes, Due 2038 [Member]
Debt Instrument [Line Items]
Interest rate		6.59%				6.59%
Senior Notes		$ 22,823		22,823
4.75% Senior Notes due 2030 [Member]
Debt Instrument [Line Items]
Interest rate												4.75%
Senior Notes		500,000		500,000								$ 500,000
Offering price, percentage of par value												97.86%
3.25% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Interest rate									3.25%		3.25%
Senior Notes									$ 263,700
Offering price, percentage of par value											104.14%
Debt instrument, repurchase amount											$ 236,300
Loss on extinguishment of debt, net		8,200		(11,100)
4.875% Senior Notes due 2049 [Member]
Debt Instrument [Line Items]
Senior Notes		300,000		300,000
3.50% Senior Notes due 2024 [Member]
Debt Instrument [Line Items]
Senior Notes		400,000		400,000
2.65% Senior Notes due 2025 [Member]
Debt Instrument [Line Items]
Senior Notes		450,000		450,000
3.00% Senior Notes due 2030 [Member]
Debt Instrument [Line Items]
Senior Notes		650,000		650,000
2.80% Senior Notes, Series E due 2024 [Member]
Debt Instrument [Line Items]
Senior Notes		474,909		471,328
Floating Rate Series F Due 2021
Debt Instrument [Line Items]
Senior Notes		0		235,664
2.50% Senior Notes Due 2031
Debt Instrument [Line Items]
Interest rate								2.50%
Senior Notes		500,000		0				$ 500,000
Public offering price as percent of par								99.74%
3.125% Senior Notes due 2023
Debt Instrument [Line Items]
Interest rate								3.125%
Senior Notes								$ 400,000
Loss on extinguishment of debt, net		$ 20,900
3.10% Senior Notes due 2023
Debt Instrument [Line Items]
Interest rate										3.10%
Senior Notes										$ 400,000
Loss on extinguishment of debt, net	$ 27,300
2.45% Senior Notes, Series G Due 2027
Debt Instrument [Line Items]
Interest rate		2.45%				2.45%
Senior Notes		$ 375,970		0		$ 475,000
Public offering price as percent of par		99.79%				99.79%
2.50% Senior Notes, Series H Due 2031
Debt Instrument [Line Items]
Interest rate		3.30%				3.30%
Senior Notes		$ 237,454		0		$ 300,000
Public offering price as percent of par		99.65%				99.65%
3.30% Senior Notes, due 2022
Debt Instrument [Line Items]
Interest rate							3.30%
Senior Notes							$ 250,000
Loss on extinguishment of debt, net		$ (800)
Repayments of debt			$ 300,000
Mortgage loans and other
Debt Instrument [Line Items]
Repayments of debt		284,700		60,900
Long-term debt, gross		2,431,831		$ 2,092,106
Mortgage loans with fixed interest rate		2,100,000
Ventas Realty Limited Partnership | Senior Notes
Debt Instrument [Line Items]
Senior Notes		7,200,000
Nationwide Health Properties, LLC | Senior Notes
Debt Instrument [Line Items]
Senior Notes		$ 75,200
Ventas Canada Finance Limited | Senior Notes
Debt Instrument [Line Items]
Senior Notes						$ 1,900,000