Accounting Policies and Related Matters (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Accounting Policies and Related Matters [Abstract]
Loss (gain) on derivatives and financial instruments, net	$ 7,173	$ (1,224)

Amount of increase (decrease) in the fair value of derivatives and financial instruments recognized in the income statement.

No definition available.

Name:	well_DerivativeGainLossOnDerivativeAndFinancialInstrumentNet
Namespace Prefix:	well_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration