Condensed Consolidating Information (Cash Flow Statement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	$ 1,437,783	$ 1,381,467	$ 1,428,752
Cash flows from investing activities:
Net investment in real estate property	(958,125)	(265,907)	(664,684)
Investment in loans receivable	(1,258,187)	(229,534)	(748,119)
Proceeds from real estate disposals	147,855	353,792	859,874
Proceeds from loans receivable	1,017,309	911,540	101,097
Development project expenditures	(403,923)	(330,876)	(299,085)
Payments for Capital Improvements	156,724	131,858	132,558
Capital expenditures	(156,724)	(131,858)	(132,558)
Distributions from unconsolidated entities	172	57,455	6,169
Investment in unconsolidated entities	(3,855)	(47,007)	(61,220)
Insurance proceeds for property damage claims	30,179	6,891	1,419
Net cash provided by (used in) investing activities	(1,585,299)	324,496	(937,107)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	(569,891)	321,463	384,783
Net change in borrowings under commercial paper program	565,524	0	0
Proceeds from debt	3,013,191	2,549,473	1,111,649
Repayment of debt	(2,623,916)	(3,465,579)	(1,369,084)
Purchase of noncontrolling interest		(4,724)	(15,809)
Net change in intercompany debt	0	0	0
Payment of deferred financing costs	(21,403)	(20,612)	(27,297)
Issuance of common stock, net	942,085	0	73,596
Cash distribution (to) from affiliates		0	0
Cash distribution to common stockholders	(1,157,720)	(1,127,143)	(827,285)
Cash distribution to redeemable OP unitholders	(9,218)	(7,459)	(5,677)
Payments for Repurchase of Other Equity	(2,203)	(1,370)	0
Purchases of redeemable OP units	(2,203)
Contributions from noncontrolling interests	6,282	1,883	4,402
Distributions to noncontrolling interests	(9,717)	(11,574)	(11,187)
Proceeds from stock option exercises	36,179	8,762	16,287
Other	(8,519)	(5,057)	(5,705)
Net cash provided by (used in) financing activities	160,674	(1,761,937)	(671,327)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	13,158	(55,974)	(179,682)
Effect of foreign currency translation	1,480	(815)	581
Effect of foreign currency translation	1,480	(815)	581
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	146,102	131,464	188,253	$ 367,354
Consolidated Elimination
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	0	0	0
Cash flows from investing activities:
Net investment in real estate property	0	0	0
Investment in loans receivable	0	0	0
Proceeds from real estate disposals	0	0	0
Proceeds from loans receivable	0	0	0
Development project expenditures	0	0	0
Payments for Capital Improvements	0	0
Capital expenditures			0
Distributions from unconsolidated entities	0	0	0
Investment in unconsolidated entities	0	0	0
Insurance proceeds for property damage claims	0	0	0
Net cash provided by (used in) investing activities	0	0	0
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	0	0	0
Net change in borrowings under commercial paper program	0
Proceeds from debt	0	0	0
Repayment of debt	0	0	0
Purchase of noncontrolling interest		0	0
Net change in intercompany debt	0	0	0
Payment of deferred financing costs	0	0	0
Issuance of common stock, net	0		0
Cash distribution (to) from affiliates		0	0
Cash distribution to common stockholders	0	0	0
Cash distribution to redeemable OP unitholders	0	0	0
Payments for Repurchase of Other Equity		0
Purchases of redeemable OP units	0
Contributions from noncontrolling interests	0	0	0
Distributions to noncontrolling interests	0	0	0
Proceeds from stock option exercises	0	0	0
Other	0	0	0
Net cash provided by (used in) financing activities	0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	0	0	0
Effect of foreign currency translation	0	0
Effect of foreign currency translation			0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0	0	0	0
Ventas, Inc.
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	59,433	45,334	149,923
Cash flows from investing activities:
Net investment in real estate property	(235,807)	(265,907)	(635,352)
Investment in loans receivable	(21,799)	(4,307)	(4,633)
Proceeds from real estate disposals	147,546	353,792	859,587
Proceeds from loans receivable	60	1,490	47
Development project expenditures	(7,240)	0	0
Payments for Capital Improvements	0	0
Capital expenditures			0
Distributions from unconsolidated entities	0	0	0
Investment in unconsolidated entities	0	0	0
Insurance proceeds for property damage claims	0	0	0
Net cash provided by (used in) investing activities	(117,240)	85,068	219,649
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	0	0	0
Net change in borrowings under commercial paper program	0
Proceeds from debt	0	0	0
Repayment of debt	0	0	0
Purchase of noncontrolling interest		(8,271)	(15,809)
Net change in intercompany debt	225,407	1,468,811	1,003,315
Payment of deferred financing costs	0	0	0
Issuance of common stock, net	942,085		73,596
Cash distribution (to) from affiliates		(490,214)	(803,257)
Cash distribution to common stockholders	(1,157,720)	(1,127,143)	(827,285)
Cash distribution to redeemable OP unitholders	0	0	0
Payments for Repurchase of Other Equity		0
Purchases of redeemable OP units	0
Contributions from noncontrolling interests	0	0	0
Distributions to noncontrolling interests	0	0	0
Proceeds from stock option exercises	36,179	8,762	16,287
Other	(8,502)	(5,057)	(5,705)
Net cash provided by (used in) financing activities	37,449	(153,112)	(558,858)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	(20,358)	(22,710)	(189,286)
Effect of foreign currency translation	12,786	(13,554)
Effect of foreign currency translation			28,442
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	3,109	10,681	46,945	207,789
Ventas Realty
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	(179,258)	(194,283)	(143,960)
Cash flows from investing activities:
Net investment in real estate property	0	0	0
Investment in loans receivable	0	0	0
Proceeds from real estate disposals	0	0	0
Proceeds from loans receivable	0	0	0
Development project expenditures	(790)	0	0
Payments for Capital Improvements	0	1,199
Capital expenditures			(726)
Distributions from unconsolidated entities	0	0	0
Investment in unconsolidated entities	0	0	0
Insurance proceeds for property damage claims	0	0	0
Net cash provided by (used in) investing activities	(790)	(1,199)	(726)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	(577,996)	326,620	478,868
Net change in borrowings under commercial paper program	565,524
Proceeds from debt	1,793,154	2,309,141	793,904
Repayment of debt	(2,109,894)	(2,954,654)	(778,606)
Purchase of noncontrolling interest		0	0
Net change in intercompany debt	525,608	530,236	(917,917)
Payment of deferred financing costs	(16,348)	(15,861)	(20,450)
Issuance of common stock, net	0		0
Cash distribution (to) from affiliates		0	587,511
Cash distribution to common stockholders	0	0	0
Cash distribution to redeemable OP unitholders	0	0	0
Payments for Repurchase of Other Equity		0
Purchases of redeemable OP units	0
Contributions from noncontrolling interests	0	0	0
Distributions to noncontrolling interests	0	0	0
Proceeds from stock option exercises	0	0	0
Other	0	0	0
Net cash provided by (used in) financing activities	180,048	195,482	143,310
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	0	0	(1,376)
Effect of foreign currency translation	0	0
Effect of foreign currency translation			0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	128	128	128	1,504
Ventas Subsidiaries
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	1,557,608	1,530,416	1,422,789
Cash flows from investing activities:
Net investment in real estate property	(722,318)	0	(29,332)
Investment in loans receivable	(1,236,388)	(225,227)	(743,486)
Proceeds from real estate disposals	309	0	287
Proceeds from loans receivable	1,017,249	910,050	101,050
Development project expenditures	(395,893)	(330,876)	(299,085)
Payments for Capital Improvements	156,724	130,659
Capital expenditures			(131,832)
Distributions from unconsolidated entities	172	57,455	6,169
Investment in unconsolidated entities	(3,855)	(47,007)	(61,220)
Insurance proceeds for property damage claims	30,179	6,891	1,419
Net cash provided by (used in) investing activities	(1,467,269)	240,627	(1,156,030)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	8,105	(5,157)	(94,085)
Net change in borrowings under commercial paper program	0
Proceeds from debt	1,220,037	240,332	317,745
Repayment of debt	(514,022)	(510,925)	(590,478)
Purchase of noncontrolling interest		3,547	0
Net change in intercompany debt	(751,015)	(1,999,047)	(85,398)
Payment of deferred financing costs	(5,055)	(4,751)	(6,847)
Issuance of common stock, net	0		0
Cash distribution (to) from affiliates		490,214	215,746
Cash distribution to common stockholders	0	0	0
Cash distribution to redeemable OP unitholders	(9,218)	(7,459)	(5,677)
Payments for Repurchase of Other Equity	(2,203)	(1,370)
Contributions from noncontrolling interests	6,282	1,883	4,402
Distributions to noncontrolling interests	(9,717)	(11,574)	(11,187)
Proceeds from stock option exercises	0	0	0
Other	(17)	0	0
Net cash provided by (used in) financing activities	(56,823)	(1,804,307)	(255,779)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect	33,516	(33,264)	10,980
Effect of foreign currency translation	(11,306)	12,739
Effect of foreign currency translation			(27,861)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 142,865	$ 120,655	$ 141,180	$ 158,061