CONDENSED CONSOLIDATING INFORMATION (Unaudited) - Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues:
Rental income	$ 401,496	$ 384,809
Income from loans and investments	17,126	31,181
Equity earnings in affiliates	0	0
Interest and other income	287	9,634
Total revenues	942,874	943,705
Expenses
Interest	110,619	111,363
Depreciation and amortization	235,920	233,150
Property-level operating expenses	430,504	412,913
Office building services costs	633	115
General, administrative and professional fees	40,760	37,174
Loss on extinguishment of debt, net	405	10,977
Merger-related expenses and deal costs	2,180	17,336
Other	23	3,120
Total expenses	821,044	826,148
Income before unconsolidated entities, real estate dispositions, income taxes, discontinued operations and noncontrolling interests	121,830	117,557
Loss from unconsolidated entities	(946)	(40,739)
Gain (Loss) on Disposition of Assets	5,447	48
Income tax benefit	1,257	3,242
Income from continuing operations	127,588	80,108
Discontinued operations	0	(10)
Net income	127,588	80,098
Net income attributable to noncontrolling interests	1,803	1,395
Net income attributable to common stockholders	125,785	78,703
Resident Fees and Services
Revenues:
Other revenues	521,447	514,753
Office Building and Other Services Revenue
Revenues:
Other revenues	2,518	3,328
Consolidated Elimination
Revenues:
Rental income	0	0
Income from loans and investments	0	0
Equity earnings in affiliates	(97,274)	(59,651)
Interest and other income	0	0
Total revenues	(97,274)	(59,651)
Expenses
Interest	0	0
Depreciation and amortization	0	0
Property-level operating expenses	0	0
Office building services costs	0	0
General, administrative and professional fees	0	0
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, real estate dispositions, income taxes, discontinued operations and noncontrolling interests	(97,274)	(59,651)
Loss from unconsolidated entities	0	0
Gain (Loss) on Disposition of Assets	0	0
Income tax benefit	0	0
Income from continuing operations	(97,274)	(59,651)
Discontinued operations	0	0
Net income	(97,274)	(59,651)
Net income attributable to noncontrolling interests	0	0
Net income attributable to common stockholders	(97,274)	(59,651)
Consolidated Elimination | Resident Fees and Services
Revenues:
Other revenues	0	0
Consolidated Elimination | Office Building and Other Services Revenue
Revenues:
Other revenues	0	0
Ventas, Inc.
Revenues:
Rental income	266	601
Income from loans and investments	423	491
Equity earnings in affiliates	97,834	60,297
Interest and other income	12	9,323
Total revenues	98,535	70,712
Expenses
Interest	(20,672)	(28,694)
Depreciation and amortization	1,351	1,344
Property-level operating expenses	0	0
Office building services costs	0	0
General, administrative and professional fees	(8,667)	557
Loss on extinguishment of debt, net	0	168
Merger-related expenses and deal costs	886	16,246
Other	(257)	2,169
Total expenses	(27,359)	(8,210)
Income before unconsolidated entities, real estate dispositions, income taxes, discontinued operations and noncontrolling interests	125,894	78,922
Loss from unconsolidated entities	0	0
Gain (Loss) on Disposition of Assets	0	0
Income tax benefit	(109)	(209)
Income from continuing operations	125,785	78,713
Discontinued operations	0	(10)
Net income	125,785	78,703
Net income attributable to noncontrolling interests	0	0
Net income attributable to common stockholders	125,785	78,703
Ventas, Inc. | Resident Fees and Services
Revenues:
Other revenues	0	0
Ventas, Inc. | Office Building and Other Services Revenue
Revenues:
Other revenues	0	0
Ventas Realty
Revenues:
Rental income	35,459	34,386
Income from loans and investments	0	0
Equity earnings in affiliates	0	0
Interest and other income	29	0
Total revenues	35,488	34,386
Expenses
Interest	83,094	82,312
Depreciation and amortization	1,388	1,444
Property-level operating expenses	162	72
Office building services costs	0	0
General, administrative and professional fees	6,468	4,050
Loss on extinguishment of debt, net	405	10,809
Merger-related expenses and deal costs	0	0
Other	1	0
Total expenses	91,518	98,687
Income before unconsolidated entities, real estate dispositions, income taxes, discontinued operations and noncontrolling interests	(56,030)	(64,301)
Loss from unconsolidated entities	0	0
Gain (Loss) on Disposition of Assets	0	0
Income tax benefit	0	0
Income from continuing operations	(56,030)	(64,301)
Discontinued operations	0	0
Net income	(56,030)	(64,301)
Net income attributable to noncontrolling interests	0	0
Net income attributable to common stockholders	(56,030)	(64,301)
Ventas Realty | Resident Fees and Services
Revenues:
Other revenues	0	0
Ventas Realty | Office Building and Other Services Revenue
Revenues:
Other revenues	0	0
Ventas Subsidiaries
Revenues:
Rental income	365,771	349,822
Income from loans and investments	16,703	30,690
Equity earnings in affiliates	(560)	(646)
Interest and other income	246	311
Total revenues	906,125	898,258
Expenses
Interest	48,197	57,745
Depreciation and amortization	233,181	230,362
Property-level operating expenses	430,342	412,841
Office building services costs	633	115
General, administrative and professional fees	42,959	32,567
Loss on extinguishment of debt, net	0	0
Merger-related expenses and deal costs	1,294	1,090
Other	279	951
Total expenses	756,885	735,671
Income before unconsolidated entities, real estate dispositions, income taxes, discontinued operations and noncontrolling interests	149,240	162,587
Loss from unconsolidated entities	(946)	(40,739)
Gain (Loss) on Disposition of Assets	5,447	48
Income tax benefit	1,366	3,451
Income from continuing operations	155,107	125,347
Discontinued operations	0	0
Net income	155,107	125,347
Net income attributable to noncontrolling interests	1,803	1,395
Net income attributable to common stockholders	153,304	123,952
Ventas Subsidiaries | Resident Fees and Services
Revenues:
Other revenues	521,447	514,753
Ventas Subsidiaries | Office Building and Other Services Revenue
Revenues:
Other revenues	$ 2,518	$ 3,328