CONDENSED CONSOLIDATING INFORMATION (Unaudited) - Statements of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Condensed financial statements, captions
Net income (loss)	$ 80,098	$ 199,148	$ 1,361,112
Other comprehensive income (loss):
Foreign currency translation	12,203	4,082
Unrealized loss on government-sponsored pooled loan investments	(172)	(123)
Other	8,615	(82)
Total other comprehensive income (loss)	20,646	3,877	$ 22,414
Comprehensive income	100,744	203,025
Comprehensive income attributable to noncontrolling interests	1,395	1,021
Comprehensive income attributable to common stockholders	99,349	202,004
Consolidated Elimination
Condensed financial statements, captions
Net income (loss)	(55,662)	(136,681)
Other comprehensive income (loss):
Foreign currency translation	0	0
Unrealized loss on government-sponsored pooled loan investments	0	0
Other	0	0
Total other comprehensive income (loss)	0	0
Comprehensive income	(55,662)	(136,681)
Comprehensive income attributable to noncontrolling interests	0	0
Comprehensive income attributable to common stockholders	(55,662)	(136,681)
Ventas, Inc.
Condensed financial statements, captions
Net income (loss)	78,703	198,127
Other comprehensive income (loss):
Foreign currency translation	0	0
Unrealized loss on government-sponsored pooled loan investments	(172)	(123)
Other	0	0
Total other comprehensive income (loss)	(172)	(123)
Comprehensive income	78,531	198,004
Comprehensive income attributable to noncontrolling interests	0	0
Comprehensive income attributable to common stockholders	78,531	198,004
Ventas Realty
Condensed financial statements, captions
Net income (loss)	(99,973)	(30,822)
Other comprehensive income (loss):
Foreign currency translation	0	0
Unrealized loss on government-sponsored pooled loan investments	0	0
Other	0	0
Total other comprehensive income (loss)	0	0
Comprehensive income	(99,973)	(30,822)
Comprehensive income attributable to noncontrolling interests	0	0
Comprehensive income attributable to common stockholders	(99,973)	(30,822)
Ventas Subsidiaries
Condensed financial statements, captions
Net income (loss)	157,030	168,524
Other comprehensive income (loss):
Foreign currency translation	12,203	4,082
Unrealized loss on government-sponsored pooled loan investments	0	0
Other	8,615	(82)
Total other comprehensive income (loss)	20,818	4,000
Comprehensive income	177,848	172,524
Comprehensive income attributable to noncontrolling interests		1,021
Comprehensive income attributable to common stockholders	$ 176,453	$ 171,503