CONDENSED CONSOLIDATING INFORMATION (Unaudited) - Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Condensed financial statements, captions
Net income (loss)	$ 103,281	$ 615,191	$ 352,679	$ 967,307	$ 1,361,112
Other comprehensive income (loss):
Foreign currency translation	(5,018)	5,239	(8,061)	17,607
Unrealized gain (loss) on marketable debt securities	5,131	(48)	17,816	(233)
Other	2,801	(936)	17,418	(620)
Total other comprehensive income	2,914	4,255	27,173	16,754	$ 22,414
Comprehensive income	106,195	619,446	379,852	984,061
Comprehensive income attributable to noncontrolling interests	1,309	1,233	5,485	3,391
Comprehensive income attributable to common stockholders	104,886	618,213	374,367	980,670
Consolidated Elimination
Condensed financial statements, captions
Net income (loss)	(73,174)	(599,008)	(276,025)	(913,158)
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	(73,174)	(599,008)	(276,025)	(913,158)
Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to common stockholders	(73,174)	(599,008)	(276,025)	(913,158)
Ventas, Inc.
Condensed financial statements, captions
Net income (loss)	101,972	613,958	347,194	963,916
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	101,972	613,958	347,194	963,916
Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to common stockholders	101,972	613,958	347,194	963,916
Ventas Realty
Condensed financial statements, captions
Net income (loss)	(87,267)	415,124	(207,818)	355,328
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	(87,267)	415,124	(207,818)	355,328
Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to common stockholders	(87,267)	415,124	(207,818)	355,328
Ventas Subsidiaries
Condensed financial statements, captions
Net income (loss)	161,750	185,117	489,328	561,221
Other comprehensive income (loss):
Foreign currency translation	(5,018)	5,239	(8,061)	17,607
Unrealized gain (loss) on marketable debt securities	5,131	(48)	17,816	(233)
Other	2,801	(936)	17,418	(620)
Total other comprehensive income	2,914	4,255	27,173	16,754
Comprehensive income	164,664	189,372	516,501	577,975
Comprehensive income attributable to noncontrolling interests	1,309	1,233	5,485	3,391
Comprehensive income attributable to common stockholders	$ 163,355	$ 188,139	$ 511,016	$ 574,584