CONDENSED CONSOLIDATING INFORMATION (Unaudited) - Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Revenues:
Rental income	$ 368,697	$ 343,783	$ 1,081,526	$ 991,878
Resident fees and services	461,974	454,825	1,390,387	1,356,384
Office building and other services revenue	4,317	10,000	17,006	29,951
Income from loans and investments	31,566	18,924	78,098	66,192
Equity earnings in affiliates	0	0	0	0
Interest and other income	562	74	792	719
Total revenues	867,116	827,606	2,567,809	2,445,124
Expenses:
Interest	105,063	97,135	312,001	263,422
Depreciation and amortization	208,387	226,332	666,735	657,262
Property-level operating expenses	361,117	347,845	1,069,294	1,031,306
Office building services costs	974	6,416	6,277	19,098
General, administrative and professional fees	31,567	32,114	95,387	100,399
(Gain) loss on extinguishment of debt, net	383	15,331	3,165	14,897
Merger-related expenses and deal costs	16,217	62,145	25,073	105,023
Other	2,430	4,795	8,901	13,948
Total expenses	726,138	792,113	2,186,833	2,205,355
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interest	140,978	35,493	380,976	239,769
Income (loss) from unconsolidated entities	931	(955)	2,151	(1,197)
Income tax benefit	8,537	10,697	28,507	27,736
Income from continuing operations	150,446	45,235	411,634	266,308
Discontinued operations	(118)	(22,383)	(755)	13,434
Gain on real estate dispositions	(144)	265	31,779	14,420
Net income	150,184	23,117	442,658	294,162	$ 419,222
Net income attributable to noncontrolling interest	732	265	1,064	1,047
Net income attributable to common stockholders	149,452	22,852	441,594	293,115
Consolidated Elimination
Revenues:
Rental income	0	0	0	0
Resident fees and services	0	0	0	0
Office building and other services revenue	0	0	0	0
Income from loans and investments	0	0	0	0
Equity earnings in affiliates	(143,501)	(99,630)	(375,657)	(360,605)
Interest and other income	0	0	0	0
Total revenues	(143,501)	(99,630)	(375,657)	(360,605)
Expenses:
Interest	0	0	0	0
Depreciation and amortization	0	0	0	0
Property-level operating expenses	0	0	0	0
Office building services costs	0	0	0	0
General, administrative and professional fees	0	0	0	0
(Gain) loss on extinguishment of debt, net	0	0	0	0
Merger-related expenses and deal costs	0	0	0	0
Other	0	0	0	0
Total expenses	0	0	0	0
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interest	(143,501)	(99,630)	(375,657)	(360,605)
Income (loss) from unconsolidated entities	0	0	0	0
Income tax benefit	0	0	0	0
Income from continuing operations	(143,501)	(99,630)	(375,657)	(360,605)
Discontinued operations	0	0	0	0
Gain on real estate dispositions	0	0	0	0
Net income	(143,501)	(99,630)	(375,657)	(360,605)
Net income attributable to noncontrolling interest	0	0	0	0
Net income attributable to common stockholders	(143,501)	(99,630)	(375,657)	(360,605)
Ventas, Inc.
Revenues:
Rental income	585	916	2,084	2,747
Resident fees and services	0	0	0	0
Office building and other services revenue	401	293	1,605	293
Income from loans and investments	82	50	82	8,655
Equity earnings in affiliates	143,782	99,873	376,570	360,988
Interest and other income	476	106	546	482
Total revenues	145,326	101,238	380,887	373,165
Expenses:
Interest	(11,779)	(10,788)	(33,668)	(27,548)
Depreciation and amortization	1,414	1,347	7,549	4,047
Property-level operating expenses	0	0	0	0
Office building services costs	0	0	0	0
General, administrative and professional fees	(1,359)	(678)	872	(598)
(Gain) loss on extinguishment of debt, net	(58)	0	0	0
Merger-related expenses and deal costs	15,952	62,007	24,067	101,306
Other	(21)	271	4	453
Total expenses	4,149	52,159	(1,176)	77,660
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interest	141,177	49,079	382,063	295,505
Income (loss) from unconsolidated entities	0	0	0	0
Income tax benefit	8,537	10,697	28,507	27,736
Income from continuing operations	149,714	59,776	410,570	323,241
Discontinued operations	(118)	(37,189)	(755)	(44,546)
Gain on real estate dispositions	(144)	265	31,779	14,420
Net income	149,452	22,852	441,594	293,115
Net income attributable to noncontrolling interest	0	0	0	0
Net income attributable to common stockholders	149,452	22,852	441,594	293,115
Ventas Realty
Revenues:
Rental income	49,652	49,425	147,795	148,833
Resident fees and services	0	0	0	0
Office building and other services revenue	0	0	0	0
Income from loans and investments	0	180	0	483
Equity earnings in affiliates	0	0	0	0
Interest and other income	0	(2)	0	(6)
Total revenues	49,652	49,603	147,795	149,310
Expenses:
Interest	70,371	67,521	207,961	189,716
Depreciation and amortization	2,833	3,455	15,614	11,394
Property-level operating expenses	80	81	236	285
Office building services costs	0	0	0	0
General, administrative and professional fees	4,940	5,225	13,657	16,640
(Gain) loss on extinguishment of debt, net	340	4,523	2,772	4,523
Merger-related expenses and deal costs	0		0	75
Other	4	5	8	49
Total expenses	78,568	80,810	240,248	222,682
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interest	(28,916)	(31,207)	(92,453)	(73,372)
Income (loss) from unconsolidated entities	783	(469)	1,230	291
Income tax benefit	0	0	0	0
Income from continuing operations	(28,133)	(31,676)	(91,223)	(73,081)
Discontinued operations	0	7,371	0	34,748
Gain on real estate dispositions	0	0	0	0
Net income	(28,133)	(24,305)	(91,223)	(38,333)
Net income attributable to noncontrolling interest	0	0	0	0
Net income attributable to common stockholders	(28,133)	(24,305)	(91,223)	(38,333)
Ventas Subsidiaries
Revenues:
Rental income	318,460	293,442	931,647	840,298
Resident fees and services	461,974	454,825	1,390,387	1,356,384
Office building and other services revenue	3,916	9,707	15,401	29,658
Income from loans and investments	31,484	18,694	78,016	57,054
Equity earnings in affiliates	(281)	(243)	(913)	(383)
Interest and other income	86	(30)	246	243
Total revenues	815,639	776,395	2,414,784	2,283,254
Expenses:
Interest	46,471	40,402	137,708	101,254
Depreciation and amortization	204,140	221,530	643,572	641,821
Property-level operating expenses	361,037	347,764	1,069,058	1,031,021
Office building services costs	974	6,416	6,277	19,098
General, administrative and professional fees	27,986	27,567	80,858	84,357
(Gain) loss on extinguishment of debt, net	101	10,808	393	10,374
Merger-related expenses and deal costs	265	138	1,006	3,642
Other	2,447	4,519	8,889	13,446
Total expenses	643,421	659,144	1,947,761	1,905,013
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interest	172,218	117,251	467,023	378,241
Income (loss) from unconsolidated entities	148	(486)	921	(1,488)
Income tax benefit	0	0	0	0
Income from continuing operations	172,366	116,765	467,944	376,753
Discontinued operations	0	7,435	0	23,232
Gain on real estate dispositions	0	0	0	0
Net income	172,366	124,200	467,944	399,985
Net income attributable to noncontrolling interest	732	265	1,064	1,047
Net income attributable to common stockholders	$ 171,634	$ 123,935	$ 466,880	$ 398,938