CONDENSED CONSOLIDATING INFORMATION (Unaudited) - Statement of Cash Flows (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	$ 729,219	$ 710,336
Cash flows from investing activities:
Net investment in real estate property	(208,039)	(12,257)
Investment in loans receivable	(507,148)	(211,554)
Proceeds from real estate disposals	74,405	312,243
Proceeds from loans receivable	289,657	866,097
Development project expenditures	(114,226)	(155,682)
Capital expenditures	(58,381)	(42,029)
Distributions from unconsolidated entities	0	6,792
Investment in unconsolidated entities	(934)	(40,033)
Insurance proceeds for property damage claims	16,939	2,329
Net cash (used in) provided by investing activities	(507,727)	725,906
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	(506,551)	(197,726)
Net change in borrowings under commercial paper program	269,810	0
Proceeds from debt	712,934	750,316
Repayment of debt	(997,061)	(1,431,887)
Purchase of noncontrolling interests	0	(2,429)
Net change in intercompany debt	0	0
Payment of deferred financing costs	(6,837)	(6,348)
Cash distribution (to) from affiliates		0
Issuance of common stock, net	866,033	0
Cash distribution to common stockholders	(567,142)	(563,395)
Cash distribution to redeemable OP unitholders	(4,551)	(3,744)
Contributions from noncontrolling interests	3,594	0
Cash issued for redemption of OP Units	0	(975)
Distributions to noncontrolling interests	(4,103)	(7,808)
Proceeds from stock option exercises	25,738	2,325
Other	(6,732)	(4,320)
Net cash used in financing activities	(214,868)	(1,465,991)
Net decrease in cash, cash equivalents and restricted cash	6,624	(29,749)
Effect of foreign currency translation	208	(401)
Cash, cash equivalents and restricted cash at beginning of period	131,464	188,253
Cash, cash equivalents and restricted cash at end of period	138,296	158,103
Consolidated Elimination
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	0	0
Cash flows from investing activities:
Net investment in real estate property	0	0
Investment in loans receivable	0	0
Proceeds from real estate disposals	0	0
Proceeds from loans receivable	0	0
Development project expenditures	0	0
Capital expenditures	0	0
Distributions from unconsolidated entities		0
Investment in unconsolidated entities	0	0
Insurance proceeds for property damage claims	0	0
Net cash (used in) provided by investing activities	0	0
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	0	0
Net change in borrowings under commercial paper program	0
Proceeds from debt	0	0
Repayment of debt	0	0
Purchase of noncontrolling interests		0
Net change in intercompany debt	0	0
Payment of deferred financing costs	0	0
Cash distribution (to) from affiliates		0
Issuance of common stock, net	0
Cash distribution to common stockholders	0	0
Cash distribution to redeemable OP unitholders	0	0
Contributions from noncontrolling interests	0
Cash issued for redemption of OP Units		0
Distributions to noncontrolling interests	0	0
Proceeds from stock option exercises	0	0
Other	0	0
Net cash used in financing activities	0	0
Net decrease in cash, cash equivalents and restricted cash	0	0
Effect of foreign currency translation	0	0
Cash, cash equivalents and restricted cash at beginning of period	0	0
Cash, cash equivalents and restricted cash at end of period	0	0
Ventas, Inc.
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	4,253	(3,651)
Cash flows from investing activities:
Net investment in real estate property	(208,039)	(12,257)
Investment in loans receivable	(19,115)	(2,830)
Proceeds from real estate disposals	74,095	312,243
Proceeds from loans receivable	33	1,452
Development project expenditures	0	0
Capital expenditures	0	0
Distributions from unconsolidated entities		6,792
Investment in unconsolidated entities	0	0
Insurance proceeds for property damage claims	0	0
Net cash (used in) provided by investing activities	(153,026)	305,400
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	0	0
Net change in borrowings under commercial paper program	0
Proceeds from debt	0	0
Repayment of debt	0	0
Purchase of noncontrolling interests		(2,429)
Net change in intercompany debt	(175,619)	237,376
Payment of deferred financing costs	0	0
Cash distribution (to) from affiliates		(7,358)
Issuance of common stock, net	866,033
Cash distribution to common stockholders	(567,142)	(563,395)
Cash distribution to redeemable OP unitholders	0	0
Contributions from noncontrolling interests	0
Cash issued for redemption of OP Units		0
Distributions to noncontrolling interests	0	0
Proceeds from stock option exercises	25,738	2,325
Other	(6,727)	(4,320)
Net cash used in financing activities	142,283	(323,085)
Net decrease in cash, cash equivalents and restricted cash	(6,490)	(21,336)
Effect of foreign currency translation	(1,640)	(7,744)
Cash, cash equivalents and restricted cash at beginning of period	10,681	46,945
Cash, cash equivalents and restricted cash at end of period	2,551	17,865
Ventas Realty
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	(90,987)	(107,438)
Cash flows from investing activities:
Net investment in real estate property	0	0
Investment in loans receivable	0	0
Proceeds from real estate disposals	0	0
Proceeds from loans receivable	0	0
Development project expenditures	0	0
Capital expenditures	0	0
Distributions from unconsolidated entities		0
Investment in unconsolidated entities	0	0
Insurance proceeds for property damage claims	0	0
Net cash (used in) provided by investing activities	0	0
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	(497,265)	(192,531)
Net change in borrowings under commercial paper program	269,810
Proceeds from debt	698,822	655,044
Repayment of debt	(958,756)	(1,311,098)
Purchase of noncontrolling interests		0
Net change in intercompany debt	585,213	961,644
Payment of deferred financing costs	(6,837)	(5,621)
Cash distribution (to) from affiliates		0
Issuance of common stock, net	0
Cash distribution to common stockholders	0	0
Cash distribution to redeemable OP unitholders	0	0
Contributions from noncontrolling interests	0
Cash issued for redemption of OP Units		0
Distributions to noncontrolling interests	0	0
Proceeds from stock option exercises	0	0
Other	0	0
Net cash used in financing activities	90,987	107,438
Net decrease in cash, cash equivalents and restricted cash	0	0
Effect of foreign currency translation	0	0
Cash, cash equivalents and restricted cash at beginning of period	128	128
Cash, cash equivalents and restricted cash at end of period	128	128
Ventas Subsidiaries
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	815,953	821,425
Cash flows from investing activities:
Net investment in real estate property	0	0
Investment in loans receivable	(488,033)	(208,724)
Proceeds from real estate disposals	310	0
Proceeds from loans receivable	289,624	864,645
Development project expenditures	(114,226)	(155,682)
Capital expenditures	(58,381)	(42,029)
Distributions from unconsolidated entities		0
Investment in unconsolidated entities	(934)	(40,033)
Insurance proceeds for property damage claims	16,939	2,329
Net cash (used in) provided by investing activities	(354,701)	420,506
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	(9,286)	(5,195)
Net change in borrowings under commercial paper program	0
Proceeds from debt	14,112	95,272
Repayment of debt	(38,305)	(120,789)
Purchase of noncontrolling interests		0
Net change in intercompany debt	(409,594)	(1,199,020)
Payment of deferred financing costs	0	(727)
Cash distribution (to) from affiliates		7,358
Issuance of common stock, net	0
Cash distribution to common stockholders	0	0
Cash distribution to redeemable OP unitholders	(4,551)	(3,744)
Contributions from noncontrolling interests	3,594
Cash issued for redemption of OP Units		(975)
Distributions to noncontrolling interests	(4,103)	(7,808)
Proceeds from stock option exercises	0	0
Other	(5)	0
Net cash used in financing activities	(448,138)	(1,250,344)
Net decrease in cash, cash equivalents and restricted cash	13,114	(8,413)
Effect of foreign currency translation	1,848	7,343
Cash, cash equivalents and restricted cash at beginning of period	120,655	141,180
Cash, cash equivalents and restricted cash at end of period	$ 135,617	$ 140,110