CONDENSED CONSOLIDATING INFORMATION (Unaudited) - Statement of Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	$ 1,086,239	$ 1,006,146
Cash flows from investing activities:
Net investment in real estate property	(262,123)	(1,421,592)
Investment in loans receivable and other	(734,033)	(154,949)
Proceeds from real estate disposals	532,137	63,561
Proceeds from loans receivable	84,361	194,063
Development project expenditures	(210,423)	(94,398)
Capital expenditures	(83,387)	(75,296)
Distributions from unconsolidated entities	5,816	0
Investment in unconsolidated entities	(42,399)	(6,175)
Net cash used in investing activities	(710,051)	(1,494,786)
Cash flows from financing activities:
Net change in borrowings under revolving credit facility	384,738	46,728
Proceeds from debt	1,058,437	876,617
Repayment of debt	(1,225,525)	(916,505)
Purchase of noncontrolling interests	(15,809)	(1,604)
Net change in intercompany debt	0	0
Payment of deferred financing costs	(26,426)	(6,147)
Issuance of common stock, net	73,596	1,265,702
Cash distribution (to) from affiliates	0	0
Cash distribution to common stockholders	(827,285)	(750,402)
Cash distribution to redeemable OP unitholders	(5,677)	(6,486)
Contributions from noncontrolling interests	4,402	5,926
Distributions to noncontrolling interests	(9,248)	(5,121)
Other	10,543	16,631
Net cash (used in) provided by financing activities	(578,254)	525,339
Net (decrease) increase in cash and cash equivalents	(202,066)	36,699
Effect of foreign currency translation on cash and cash equivalents	422	(443)
Cash and cash equivalents at beginning of period	286,707	53,023
Cash and cash equivalents at end of period	85,063	89,279
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 and other	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
Net cash used in investing activities	0	0
Cash flows from financing activities:
Net change in borrowings under revolving credit facility	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	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
Distributions to noncontrolling interests	0	0
Other	0	0
Net cash (used in) provided by financing activities	0	0
Net (decrease) increase in cash and cash equivalents	0	0
Effect of foreign currency translation on cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0	0
Ventas, Inc.
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	60,228	44,088
Cash flows from investing activities:
Net investment in real estate property	(232,791)	(1,440,710)
Investment in loans receivable and other	(2,727)	0
Proceeds from real estate disposals	531,637	20,441
Proceeds from loans receivable	36	0
Development project expenditures	0	0
Capital expenditures	0	0
Distributions from unconsolidated entities	0
Investment in unconsolidated entities	0	0
Net cash used in investing activities	296,155	(1,420,269)
Cash flows from financing activities:
Net change in borrowings under revolving credit facility	0	0
Proceeds from debt	0	0
Repayment of debt	0	0
Purchase of noncontrolling interests	(15,809)	0
Net change in intercompany debt	741,457	877,609
Payment of deferred financing costs	0	0
Issuance of common stock, net	73,596	1,265,702
Cash distribution (to) from affiliates	(560,606)	8,206
Cash distribution to common stockholders	(827,285)	(750,402)
Cash distribution to redeemable OP unitholders	0	0
Contributions from noncontrolling interests	0	0
Distributions to noncontrolling interests	0	0
Other	10,543	16,631
Net cash (used in) provided by financing activities	(578,104)	1,417,746
Net (decrease) increase in cash and cash equivalents	(221,721)	41,565
Effect of foreign currency translation on cash and cash equivalents	25,481	(41,259)
Cash and cash equivalents at beginning of period	210,303	11,733
Cash and cash equivalents at end of period	14,063	12,039
Ventas Realty
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	(86,406)	(73,848)
Cash flows from investing activities:
Net investment in real estate property	0	0
Investment in loans receivable and other	0	0
Proceeds from real estate disposals	0	0
Proceeds from loans receivable	0	0
Development project expenditures	0	0
Capital expenditures	(604)	(18)
Distributions from unconsolidated entities	0
Investment in unconsolidated entities	0	0
Net cash used in investing activities	(604)	(18)
Cash flows from financing activities:
Net change in borrowings under revolving credit facility	467,000	(94,000)
Proceeds from debt	793,904	846,521
Repayment of debt	(778,606)	(651,820)
Purchase of noncontrolling interests	0	0
Net change in intercompany debt	(748,586)	(32,967)
Payment of deferred financing costs	(20,450)	(5,485)
Issuance of common stock, net	0	0
Cash distribution (to) from affiliates	373,748	11,617
Cash distribution to common stockholders	0	0
Cash distribution to redeemable OP unitholders	0	0
Contributions from noncontrolling interests	0	0
Distributions to noncontrolling interests	0	0
Other	0	0
Net cash (used in) provided by financing activities	87,010	73,866
Net (decrease) increase in cash and cash equivalents	0
Effect of foreign currency translation on cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0
Cash and cash equivalents at end of period	0
Ventas Subsidiaries
Condensed Consolidating Statement of Cash Flows
Net cash provided by (used in) operating activities	1,112,417	1,035,906
Cash flows from investing activities:
Net investment in real estate property	(29,332)	19,118
Investment in loans receivable and other	(731,306)	(154,949)
Proceeds from real estate disposals	500	43,120
Proceeds from loans receivable	84,325	194,063
Development project expenditures	(210,423)	(94,398)
Capital expenditures	(82,783)	(75,278)
Distributions from unconsolidated entities	5,816
Investment in unconsolidated entities	(42,399)	(6,175)
Net cash used in investing activities	(1,005,602)	(74,499)
Cash flows from financing activities:
Net change in borrowings under revolving credit facility	(82,262)	140,728
Proceeds from debt	264,533	30,096
Repayment of debt	(446,919)	(264,685)
Purchase of noncontrolling interests	0	(1,604)
Net change in intercompany debt	7,129	(844,642)
Payment of deferred financing costs	(5,976)	(662)
Issuance of common stock, net	0	0
Cash distribution (to) from affiliates	186,858	(19,823)
Cash distribution to common stockholders	0	0
Cash distribution to redeemable OP unitholders	(5,677)	(6,486)
Contributions from noncontrolling interests	4,402	5,926
Distributions to noncontrolling interests	(9,248)	(5,121)
Other	0	0
Net cash (used in) provided by financing activities	(87,160)	(966,273)
Net (decrease) increase in cash and cash equivalents	19,655	(4,866)
Effect of foreign currency translation on cash and cash equivalents	(25,059)	40,816
Cash and cash equivalents at beginning of period	76,404	41,290
Cash and cash equivalents at end of period	$ 71,000	$ 77,240