CONDENSED CONSOLIDATING INFORMATION (Unaudited) - Statement of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	$ 1,017,622	$ 1,082,225
Cash flows from investing activities:
Net investment in real estate property	(35,800)	(346,491)
Investment in loans receivable	(212,089)	(734,033)
Proceeds from real estate disposals	331,243	614,753
Proceeds from loans receivable	866,313	84,361
Development project expenditures	(230,348)	(210,423)
Capital expenditures	(73,025)	(83,387)
Distributions from unconsolidated entities	57,430	5,816
Investment in unconsolidated entities	(45,106)	(42,399)
Insurance proceeds for property damage claims	6,327	1,393
Net cash provided by (used in) investing activities	664,945	(710,410)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	41,292	384,738
Proceeds from debt	2,412,420	1,058,437
Repayment of debt	(3,294,104)	(1,225,525)
Purchase of noncontrolling interests	2,429	15,809
Net change in intercompany debt	0	0
Payment of deferred financing costs	(16,583)	(26,426)
Issuance of common stock, net	0	73,596
Cash distribution (to) from affiliates	0	0
Cash distribution to common stockholders	(845,248)	(827,285)
Cash distribution to redeemable OP Unitholders	(5,594)	(5,677)
Contributions from noncontrolling interests	500	4,402
Cash issued for redemption of OP and Class C Units	(1,370)	0
Distributions to noncontrolling interests	(9,968)	(9,248)
Other	(736)	10,543
Net cash used in financing activities	(1,721,820)	(578,254)
Net decrease in cash, cash equivalents and restricted cash	(39,253)	(206,439)
Effect of foreign currency translation	(453)	670
Cash, cash equivalents and restricted cash at beginning of period	188,253	367,354
Cash, cash equivalents and restricted cash at end of period	148,547	161,585
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	0
Investment in unconsolidated entities	0	0
Insurance proceeds for property damage claims	0	0
Net cash provided by (used in) investing activities	0	0
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	0	0
Proceeds from debt	0	0
Repayment of debt	0	0
Purchase of noncontrolling interests	0	0
Net change in intercompany debt	0	0
Payment of deferred financing costs	0	0
Issuance of common stock, net		0
Cash distribution (to) from affiliates	0	0
Cash distribution to common stockholders	0	0
Cash distribution to redeemable OP Unitholders	0	0
Contributions from noncontrolling interests	0	0
Cash issued for redemption of OP and Class C Units	0
Distributions to noncontrolling interests	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	30,077	60,382
Cash flows from investing activities:
Net investment in real estate property	(35,800)	(317,785)
Investment in loans receivable	(3,036)	(2,727)
Proceeds from real estate disposals	331,243	616,637
Proceeds from loans receivable	1,473	36
Development project expenditures	0	0
Capital expenditures	0	0
Distributions from unconsolidated entities	0	0
Investment in unconsolidated entities	0	0
Insurance proceeds for property damage claims	0	0
Net cash provided by (used in) investing activities	293,880	296,161
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	0	0
Proceeds from debt	0	0
Repayment of debt	0	0
Purchase of noncontrolling interests	2,429	15,809
Net change in intercompany debt	976,533	743,966
Payment of deferred financing costs	0	0
Issuance of common stock, net		73,596
Cash distribution (to) from affiliates	(473,343)	(562,534)
Cash distribution to common stockholders	(845,248)	(827,285)
Cash distribution to redeemable OP Unitholders	0	0
Contributions from noncontrolling interests	0	0
Cash issued for redemption of OP and Class C Units	0
Distributions to noncontrolling interests	0	0
Other	(736)	10,543
Net cash used in financing activities	(345,223)	(577,523)
Net decrease in cash, cash equivalents and restricted cash	(21,266)	(220,980)
Effect of foreign currency translation	(12,190)	25,481
Cash, cash equivalents and restricted cash at beginning of period	46,945	207,789
Cash, cash equivalents and restricted cash at end of period	13,489	12,290
Ventas Realty
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	(163,311)	(87,781)
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	(604)
Distributions from unconsolidated entities	0	0
Investment in unconsolidated entities	0	0
Insurance proceeds for property damage claims	0	0
Net cash provided by (used in) investing activities	0	(604)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	49,438	467,000
Proceeds from debt	2,309,141	793,904
Repayment of debt	(2,949,456)	(778,606)
Purchase of noncontrolling interests	0	0
Net change in intercompany debt	769,781	(748,587)
Payment of deferred financing costs	(15,593)	(20,450)
Issuance of common stock, net		0
Cash distribution (to) from affiliates	0	373,748
Cash distribution to common stockholders	0	0
Cash distribution to redeemable OP Unitholders	0	0
Contributions from noncontrolling interests	0	0
Cash issued for redemption of OP and Class C Units	0
Distributions to noncontrolling interests	0	0
Other	0	0
Net cash used in financing activities	163,311	87,009
Net decrease in cash, cash equivalents and restricted cash	0	(1,376)
Effect of foreign currency translation	0	0
Cash, cash equivalents and restricted cash at beginning of period	128	1,504
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	1,150,856	1,109,624
Cash flows from investing activities:
Net investment in real estate property	0	(28,706)
Investment in loans receivable	(209,053)	(731,306)
Proceeds from real estate disposals	0	(1,884)
Proceeds from loans receivable	864,840	84,325
Development project expenditures	(230,348)	(210,423)
Capital expenditures	(73,025)	(82,783)
Distributions from unconsolidated entities	57,430	5,816
Investment in unconsolidated entities	(45,106)	(42,399)
Insurance proceeds for property damage claims	6,327	1,393
Net cash provided by (used in) investing activities	371,065	(1,005,967)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	(8,146)	(82,262)
Proceeds from debt	103,279	264,533
Repayment of debt	(344,648)	(446,919)
Purchase of noncontrolling interests	0	0
Net change in intercompany debt	(1,746,314)	4,621
Payment of deferred financing costs	(990)	(5,976)
Issuance of common stock, net		0
Cash distribution (to) from affiliates	473,343	188,786
Cash distribution to common stockholders	0	0
Cash distribution to redeemable OP Unitholders	(5,594)	(5,677)
Contributions from noncontrolling interests	500	4,402
Cash issued for redemption of OP and Class C Units	(1,370)
Distributions to noncontrolling interests	(9,968)	(9,248)
Other	0	0
Net cash used in financing activities	(1,539,908)	(87,740)
Net decrease in cash, cash equivalents and restricted cash	(17,987)	15,917
Effect of foreign currency translation	11,737	(24,811)
Cash, cash equivalents and restricted cash at beginning of period	141,180	158,061
Cash, cash equivalents and restricted cash at end of period	$ 134,930	$ 149,167