ACCOUNTING POLICIES - Schedule of VIEs (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Variable Interest Entity
Assets	$ 26,617,828	$ 24,692,208
Liabilities	15,703,730	13,873,078
Variable Interest Entity | NHP/PMB L.P.
Variable Interest Entity
Assets	661,649	666,404
Liabilities	240,099	244,934
Variable Interest Entity | Other Identified VIEs
Variable Interest Entity
Assets	3,727,402	4,075,821
Liabilities	1,386,629	1,459,830
Variable Interest Entity | Tax Credit VIEs
Variable Interest Entity
Assets	887,976	845,229
Liabilities	$ 343,825	$ 333,809