CONDENSED CONSOLIDATING INFORMATION (Unaudited) - Statement of Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Revenues:
Rental income	$ 399,498	$ 354,206	$ 794,720	$ 712,829
Resident fees and services	460,243	464,437	924,431	928,413
Office building and other services revenue	3,179	5,504	6,585	12,689
Income from loans and investments	32,368	24,146	52,514	46,532
Equity earnings in affiliates	0	0	0	0
Interest and other income	202	111	683	230
Total revenues	895,490	848,404	1,778,933	1,700,693
Expenses
Interest	113,572	103,665	222,376	206,938
Depreciation and amortization	224,108	221,961	441,891	458,348
Property-level operating expenses	365,830	351,955	734,817	708,177
Office building services costs	552	1,852	1,290	5,303
General, administrative and professional fees	33,282	32,094	67,243	63,820
Loss (gain) on extinguishment of debt, net	36	2,468	345	2,782
Merger-related expenses and deal costs	6,043	7,224	8,099	8,856
Other	1,848	2,303	3,036	6,471
Total expenses	745,271	723,522	1,479,097	1,460,695
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interests	150,219	124,882	299,836	239,998
Income (loss) from unconsolidated entities	(106)	1,418	3,044	1,220
Income tax benefit	2,159	11,549	5,304	19,970
Income from continuing operations	152,272	137,849	308,184	261,188
Discontinued operations	(23)	(148)	(76)	(637)
Gain on real estate dispositions	719	5,739	44,008	31,923
Net income	152,968	143,440	352,116	292,474	$ 651,490
Net income attributable to noncontrolling interests	1,137	278	2,158	332
Net income attributable to common stockholders	151,831	143,162	349,958	292,142
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	(127,791)	(123,740)	(264,475)	(232,159)
Interest and other income	0	0	0	0
Total revenues	(127,791)	(123,740)	(264,475)	(232,159)
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
Loss (gain) 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 interests	(127,791)	(123,740)	(264,475)	(232,159)
Income (loss) from unconsolidated entities	0	0	0	0
Income tax benefit	0	0	0	0
Income from continuing operations	(127,791)	(123,740)	(264,475)	(232,159)
Discontinued operations		0	0	0
Gain on real estate dispositions		0	0	0
Net income	(127,791)	(123,740)	(264,475)	(232,159)
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to common stockholders	(127,791)	(123,740)	(264,475)	(232,159)
Ventas, Inc.
Revenues:
Rental income	596	583	1,181	1,499
Resident fees and services	0	0	0	0
Office building and other services revenue	0	602	0	1,204
Income from loans and investments	319	0	599	0
Equity earnings in affiliates	128,196	124,028	265,188	232,790
Interest and other income	28	41	371	70
Total revenues	129,139	125,254	267,339	235,563
Expenses
Interest	(27,694)	(11,094)	(44,293)	(21,889)
Depreciation and amortization	1,419	1,203	2,826	6,135
Property-level operating expenses	0	0	0	0
Office building services costs	0	0	0	0
General, administrative and professional fees	189	2,246	319	2,231
Loss (gain) on extinguishment of debt, net	0	58	0	58
Merger-related expenses and deal costs	5,783	6,743	7,646	8,115
Other	466	76	119	27
Total expenses	(19,837)	(768)	(33,383)	(5,323)
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interests	148,976	126,022	300,722	240,886
Income (loss) from unconsolidated entities	0	0	0	0
Income tax benefit	2,159	11,549	5,304	19,970
Income from continuing operations	151,135	137,571	306,026	260,856
Discontinued operations	(23)	(148)	(76)	(637)
Gain on real estate dispositions	719	5,739	44,008	31,923
Net income	151,831	143,162	349,958	292,142
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to common stockholders	151,831	143,162	349,958	292,142
Ventas Realty
Revenues:
Rental income	48,451	49,418	96,270	98,143
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	0	0	0	0
Interest and other income	0	0	0	0
Total revenues	48,451	49,418	96,270	98,143
Expenses
Interest	81,516	69,011	156,303	137,590
Depreciation and amortization	2,239	2,867	4,608	12,781
Property-level operating expenses	83	77	165	156
Office building services costs	0	0	0	0
General, administrative and professional fees	4,630	4,213	9,330	8,717
Loss (gain) on extinguishment of debt, net	418	2,432	439	2,432
Merger-related expenses and deal costs	0	0	0	0
Other	0	4	0	4
Total expenses	88,886	78,604	170,845	161,680
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interests	(40,435)	(29,186)	(74,575)	(63,537)
Income (loss) from unconsolidated entities	(16)	344	3,305	447
Income tax benefit	0	0	0	0
Income from continuing operations	(40,451)	(28,842)	(71,270)	(63,090)
Discontinued operations		0	0	0
Gain on real estate dispositions		0	0	0
Net income	(40,451)	(28,842)	(71,270)	(63,090)
Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to common stockholders	(40,451)	(28,842)	(71,270)	(63,090)
Ventas Subsidiaries
Revenues:
Rental income	350,451	304,205	697,269	613,187
Resident fees and services	460,243	464,437	924,431	928,413
Office building and other services revenue	3,179	4,902	6,585	11,485
Income from loans and investments	32,049	24,146	51,915	46,532
Equity earnings in affiliates	(405)	(288)	(713)	(631)
Interest and other income	174	70	312	160
Total revenues	845,691	797,472	1,679,799	1,599,146
Expenses
Interest	59,750	45,748	110,366	91,237
Depreciation and amortization	220,450	217,891	434,457	439,432
Property-level operating expenses	365,747	351,878	734,652	708,021
Office building services costs	552	1,852	1,290	5,303
General, administrative and professional fees	28,463	25,635	57,594	52,872
Loss (gain) on extinguishment of debt, net	(382)	(22)	(94)	292
Merger-related expenses and deal costs	260	481	453	741
Other	1,382	2,223	2,917	6,440
Total expenses	676,222	645,686	1,341,635	1,304,338
Income before unconsolidated entities, income taxes, discontinued operations, real estate dispositions and noncontrolling interests	169,469	151,786	338,164	294,808
Income (loss) from unconsolidated entities	(90)	1,074	(261)	773
Income tax benefit	0	0	0	0
Income from continuing operations	169,379	152,860	337,903	295,581
Discontinued operations		0	0	0
Gain on real estate dispositions		0	0	0
Net income	169,379	152,860	337,903	295,581
Net income attributable to noncontrolling interests	1,137	278	2,158	332
Net income attributable to common stockholders	$ 168,242	$ 152,582	$ 335,745	$ 295,249