CONDENSED CONSOLIDATING INFORMATION (Unaudited) - Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Condensed financial statements, captions
Net income (loss)	$ 169,300	$ 152,968	$ 249,398	$ 352,116	$ 1,361,112
Other comprehensive income (loss):
Foreign currency translation	(15,246)	8,286	(3,043)	12,368
Unrealized gain (loss) on marketable debt securities	12,857	(62)	12,685	(185)
Other	6,002	398	14,617	316
Total other comprehensive income	3,613	8,622	24,259	12,499	$ 22,414
Comprehensive income	172,913	161,590	273,657	364,615
Comprehensive income attributable to noncontrolling interests	2,781	1,137	4,176	2,158
Comprehensive income attributable to common stockholders	170,132	160,453	269,481	362,457
Consolidated Elimination
Condensed financial statements, captions
Net income (loss)	(143,197)	(130,806)	(202,849)	(314,153)
Other comprehensive income (loss):
Foreign currency translation	0	0	0	0
Unrealized gain (loss) on marketable debt securities	0	0	0	0
Other	0	0	0	0
Total other comprehensive income	0	0	0	0
Comprehensive income	(143,197)	(130,806)	(202,849)	(314,153)
Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to common stockholders	(143,197)	(130,806)	(202,849)	(314,153)
Ventas, Inc.
Condensed financial statements, captions
Net income (loss)	166,519	151,831	245,222	349,958
Other comprehensive income (loss):
Foreign currency translation	0	0	0	0
Unrealized gain (loss) on marketable debt securities	0	0	0	0
Other	0	0	0	0
Total other comprehensive income	0		0	0
Comprehensive income	166,519	151,831	245,222	349,958
Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to common stockholders	166,519	151,831	245,222	349,958
Ventas Realty
Condensed financial statements, captions
Net income (loss)	(56,250)	(40,435)	(120,551)	(59,796)
Other comprehensive income (loss):
Foreign currency translation	0	0	0	0
Unrealized gain (loss) on marketable debt securities	0	0	0	0
Other	0	0	0	0
Total other comprehensive income	0	0	0	0
Comprehensive income	(56,250)	(40,435)	(120,551)	(59,796)
Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to common stockholders	(56,250)	(40,435)	(120,551)	(59,796)
Ventas Subsidiaries
Condensed financial statements, captions
Net income (loss)	202,228	172,378	327,576	376,107
Other comprehensive income (loss):
Foreign currency translation	(15,246)	8,286	(3,043)	12,368
Unrealized gain (loss) on marketable debt securities	12,857	(62)	12,685	(185)
Other	6,002	398	14,617	316
Total other comprehensive income	3,613	8,622	24,259	12,499
Comprehensive income	205,841	181,000	351,835	388,606
Comprehensive income attributable to noncontrolling interests	2,781	1,137	4,176	2,158
Comprehensive income attributable to common stockholders	$ 203,060	$ 179,863	$ 347,659	$ 386,448