Condensed Consolidating Information (Cash Flow Statement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	$ 1,381,467	$ 1,428,752	$ 1,354,702
Cash flows from investing activities:
Net investment in real estate property	(265,907)	(664,684)	(1,413,595)
Investment in loans receivable and other	(229,534)	(748,119)	(158,635)
Proceeds from real estate disposals	353,792	859,874	300,561
Proceeds from loans receivable	911,540	101,097	320,082
Development project expenditures	(330,876)	(299,085)	(143,647)
Capital expenditures	(131,858)	(132,558)	(117,456)
Distributions from unconsolidated entities	57,455	6,169	0
Investment in unconsolidated entities	(47,007)	(61,220)	(6,436)
Insurance proceeds for property damage claims	6,891	1,419	4,846
Net cash provided by (used in) investing activities	324,496	(937,107)	(1,214,280)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	321,463	384,783	(35,637)
Proceeds from debt	2,549,473	1,111,649	893,218
Repayment of debt	(3,465,579)	(1,369,084)	(1,022,113)
Purchase of noncontrolling interest	(4,724)	(15,809)	(2,846)
Net change in intercompany debt	0	0	0
Payment of deferred financing costs	(20,612)	(27,297)	(6,555)
Issuance of common stock, net	0	73,596	1,286,680
Cash distribution (to) from affiliates	0	0	0
Cash distribution to common stockholders	(1,127,143)	(827,285)	(1,024,968)
Cash distribution to redeemable OP Unitholders	(7,459)	(5,677)	(8,640)
Purchases of redeemable OP units	(1,370)		0
Contributions from noncontrolling interests	1,883	4,402	7,326
Distributions to noncontrolling interests	(11,574)	(11,187)	(6,879)
Other	3,705	10,582	17,252
Net cash (used in) provided by financing activities	(1,761,937)	(671,327)	96,838
Net (decrease) increase in cash, cash equivalents and restricted cash	(55,974)	(179,682)	237,260
Effect of foreign currency translation	(815)	581	(825)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	131,464	188,253	367,354	$ 130,919
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 and other	0	0	0
Proceeds from real estate disposals	0	0	0
Proceeds from loans receivable	0	0	0
Development project expenditures	0	0	0
Capital expenditures	0	0	0
Distributions from unconsolidated entities	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
Proceeds from debt	0	0	0
Repayment of debt	0	0	0
Purchase of noncontrolling interest	0	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	0
Cash distribution to common stockholders	0	0	0
Cash distribution to redeemable OP Unitholders	0	0	0
Purchases of redeemable OP units	0		0
Contributions from noncontrolling interests	0	0	0
Distributions to noncontrolling interests	0	0	0
Other	0	0	0
Net cash (used in) provided by financing activities	0	0	0
Net (decrease) increase in cash, cash equivalents and restricted cash	0	0	0
Effect of foreign currency translation	0	0	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	45,334	149,923	68,567
Cash flows from investing activities:
Net investment in real estate property	(265,907)	(635,352)	(1,455,184)
Investment in loans receivable and other	(4,307)	(4,633)	0
Proceeds from real estate disposals	353,792	859,587	257,441
Proceeds from loans receivable	1,490	47	0
Development project expenditures	0	0	0
Capital expenditures	0	0	0
Distributions from unconsolidated entities	0	0
Investment in unconsolidated entities	0	0	0
Insurance proceeds for property damage claims		0	0
Net cash provided by (used in) investing activities	85,068	219,649	(1,197,743)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	0	0	0
Proceeds from debt	0	0	0
Repayment of debt	0	0	0
Purchase of noncontrolling interest	(8,271)	(15,809)	0
Net change in intercompany debt	1,468,811	1,003,315	990,969
Payment of deferred financing costs	0	0	0
Issuance of common stock, net		73,596	1,286,680
Cash distribution (to) from affiliates	(490,214)	(803,257)	107,289
Cash distribution to common stockholders	(1,127,143)	(827,285)	(1,024,968)
Cash distribution to redeemable OP Unitholders	0	0	0
Purchases of redeemable OP units	0		0
Contributions from noncontrolling interests	0	0	0
Distributions to noncontrolling interests	0	0	0
Other	3,705	10,582	17,252
Net cash (used in) provided by financing activities	(153,112)	(558,858)	1,377,222
Net (decrease) increase in cash, cash equivalents and restricted cash	(22,710)	(189,286)	248,046
Effect of foreign currency translation	(13,554)	28,442	(56,389)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	10,681	46,945	207,789	16,132
Ventas Realty
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	(194,283)	(143,960)	(93,005)
Cash flows from investing activities:
Net investment in real estate property	0	0	0
Investment in loans receivable and other	0	0	0
Proceeds from real estate disposals	0	0	0
Proceeds from loans receivable	0	0	0
Development project expenditures	0	0	0
Capital expenditures	(1,199)	(726)	(314)
Distributions from unconsolidated entities	0	0
Investment in unconsolidated entities	0	0	0
Insurance proceeds for property damage claims		0	0
Net cash provided by (used in) investing activities	(1,199)	(726)	(314)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	326,620	478,868	(171,000)
Proceeds from debt	2,309,141	793,904	846,521
Repayment of debt	(2,954,654)	(778,606)	(651,820)
Purchase of noncontrolling interest	0	0	0
Net change in intercompany debt	530,236	(917,917)	84,627
Payment of deferred financing costs	(15,861)	(20,450)	(5,787)
Issuance of common stock, net		0	0
Cash distribution (to) from affiliates	0	587,511	(9,362)
Cash distribution to common stockholders	0	0	0
Cash distribution to redeemable OP Unitholders	0	0	0
Purchases of redeemable OP units	0		0
Contributions from noncontrolling interests	0	0	0
Distributions to noncontrolling interests	0	0	0
Other	0	0	0
Net cash (used in) provided by financing activities	195,482	143,310	93,179
Net (decrease) increase in cash, cash equivalents and restricted cash	0	(1,376)	(140)
Effect of foreign currency translation	0	0	0
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	128	128	1,504	1,644
Ventas Subsidiaries
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	1,530,416	1,422,789	1,379,140
Cash flows from investing activities:
Net investment in real estate property	0	(29,332)	41,589
Investment in loans receivable and other	(225,227)	(743,486)	(158,635)
Proceeds from real estate disposals	0	287	43,120
Proceeds from loans receivable	910,050	101,050	320,082
Development project expenditures	(330,876)	(299,085)	(143,647)
Capital expenditures	(130,659)	(131,832)	(117,142)
Distributions from unconsolidated entities	57,455	6,169
Investment in unconsolidated entities	(47,007)	(61,220)	(6,436)
Insurance proceeds for property damage claims	6,891	1,419	4,846
Net cash provided by (used in) investing activities	240,627	(1,156,030)	(16,223)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	(5,157)	(94,085)	135,363
Proceeds from debt	240,332	317,745	46,697
Repayment of debt	(510,925)	(590,478)	(370,293)
Purchase of noncontrolling interest	3,547	0	(2,846)
Net change in intercompany debt	(1,999,047)	(85,398)	(1,075,596)
Payment of deferred financing costs	(4,751)	(6,847)	(768)
Issuance of common stock, net		0	0
Cash distribution (to) from affiliates	490,214	215,746	(97,927)
Cash distribution to common stockholders	0	0	0
Cash distribution to redeemable OP Unitholders	(7,459)	(5,677)	(8,640)
Purchases of redeemable OP units	(1,370)		0
Contributions from noncontrolling interests	1,883	4,402	7,326
Distributions to noncontrolling interests	(11,574)	(11,187)	(6,879)
Other	0	0	0
Net cash (used in) provided by financing activities	(1,804,307)	(255,779)	(1,373,563)
Net (decrease) increase in cash, cash equivalents and restricted cash	(33,264)	10,980	(10,646)
Effect of foreign currency translation	12,739	(27,861)	55,564
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 120,655	$ 141,180	$ 158,061	$ 113,143