CONDENSED CONSOLIDATING INFORMATION - Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Revenues:
Rental income	$ 358,623	$ 325,617
Resident fees and services	463,976	446,914
Medical office building and other services revenue	7,185	10,543
Income from loans and investments	22,386	22,053
Equity earnings in affiliates	0	0
Interest and other income	119	471
Total revenues	852,289	805,598
Expenses:
Interest	103,273	82,328
Depreciation and amortization	236,387	216,219
Property-level operating expenses	356,222	340,799
Medical office building services costs	3,451	6,918
General, administrative and professional fees	31,726	34,326
(Gain) loss on extinguishment of debt, net	314	21
Merger-related expenses and deal costs	1,632	30,613
Other	4,168	4,874
Total expenses	737,173	716,098
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interest	115,116	89,500
Income (loss) from unconsolidated entities	(198)	(251)
Income tax benefit	8,421	7,250
Income from continuing operations	123,339	96,499
Discontinued operations	(489)	17,574
Gain on real estate dispositions	26,184	6,686
Net income	149,034	120,759	$ 419,222
Net income attributable to noncontrolling interest	54	317
Net income attributable to common stockholders	148,980	120,442
Consolidated Elimination
Revenues:
Rental income	0	0
Resident fees and services	0	0
Medical office building and other services revenue	0	0
Income from loans and investments	0	0
Equity earnings in affiliates	(108,420)	(129,917)
Interest and other income	0	0
Total revenues	(108,420)	(129,917)
Expenses:
Interest	0	0
Depreciation and amortization	0	0
Property-level operating expenses	0	0
Medical office building services costs	0	0
General, administrative and professional fees	0	0
(Gain) loss on extinguishment of debt, net	0	0
Merger-related expenses and deal costs	0	0
Other	0	0
Total expenses	0	0
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interest	(108,420)	(129,917)
Income (loss) from unconsolidated entities	0	0
Income tax benefit	0	0
Income from continuing operations	(108,420)	(129,917)
Discontinued operations	0	0
Gain on real estate dispositions	0	0
Net income	(108,420)	(129,917)
Net income attributable to noncontrolling interest	0	0
Net income attributable to common stockholders	(108,420)	(129,917)
Ventas, Inc.
Revenues:
Rental income	916	916
Resident fees and services	0	0
Medical office building and other services revenue	602	0
Income from loans and investments	0	1,436
Equity earnings in affiliates	108,762	129,995
Interest and other income	29	356
Total revenues	110,309	132,703
Expenses:
Interest	(10,795)	(7,829)
Depreciation and amortization	4,932	1,342
Property-level operating expenses	0	0
Medical office building services costs	0	0
General, administrative and professional fees	(15)	(2,741)
(Gain) loss on extinguishment of debt, net	0	0
Merger-related expenses and deal costs	1,372	29,793
Other	(49)	647
Total expenses	(4,555)	21,212
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interest	114,864	111,491
Income (loss) from unconsolidated entities	0	0
Income tax benefit	8,421	7,250
Income from continuing operations	123,285	118,741
Discontinued operations	(489)	(4,985)
Gain on real estate dispositions	26,184	6,686
Net income	148,980	120,442
Net income attributable to noncontrolling interest	0	0
Net income attributable to common stockholders	$ 148,980	120,442
Ventas Realty
Condensed financial statements, captions
Ownership percentage	100.00%
Revenues:
Rental income	$ 48,725	49,788
Resident fees and services	0	0
Medical office building and other services revenue	0	0
Income from loans and investments	0	51
Equity earnings in affiliates	0	0
Interest and other income	0	5
Total revenues	48,725	49,844
Expenses:
Interest	68,579	60,623
Depreciation and amortization	9,914	4,434
Property-level operating expenses	79	131
Medical office building services costs	0	0
General, administrative and professional fees	4,504	6,361
(Gain) loss on extinguishment of debt, net	0	0
Merger-related expenses and deal costs	0	0
Other	0	4
Total expenses	83,076	71,553
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interest	(34,351)	(21,709)
Income (loss) from unconsolidated entities	103	401
Income tax benefit	0	0
Income from continuing operations	(34,248)	(21,308)
Discontinued operations	0	13,520
Gain on real estate dispositions	0	0
Net income	(34,248)	(7,788)
Net income attributable to noncontrolling interest	0	0
Net income attributable to common stockholders	(34,248)	(7,788)
Ventas Subsidiaries
Revenues:
Rental income	308,982	274,913
Resident fees and services	463,976	446,914
Medical office building and other services revenue	6,583	10,543
Income from loans and investments	22,386	20,566
Equity earnings in affiliates	(342)	(78)
Interest and other income	90	110
Total revenues	801,675	752,968
Expenses:
Interest	45,489	29,534
Depreciation and amortization	221,541	210,443
Property-level operating expenses	356,143	340,668
Medical office building services costs	3,451	6,918
General, administrative and professional fees	27,237	30,706
(Gain) loss on extinguishment of debt, net	314	21
Merger-related expenses and deal costs	260	820
Other	4,217	4,223
Total expenses	658,652	623,333
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interest	143,023	129,635
Income (loss) from unconsolidated entities	(301)	(652)
Income tax benefit	0	0
Income from continuing operations	142,722	128,983
Discontinued operations	0	9,039
Gain on real estate dispositions	0	0
Net income	142,722	138,022
Net income attributable to noncontrolling interest	54	317
Net income attributable to common stockholders	$ 142,668	$ 137,705
Ventas Capital Corporation
Condensed financial statements, captions
Ownership percentage	100.00%	100.00%	100.00%