SUMMARY OF ACCOUNTING POLICIES - Other Current Assets and Investments (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2018	Jun. 29, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Intangible amortization					$ 64,106	$ 74,396	$ 78,640
Investments in non-consolidated companies	$ 128,100	$ 294,100			128,100	294,100
Non-core investment impairment charges					98,000
Investment impairments and dispositions					97,691	193,063	21,895
Gain on deconsolidation					0	86,614	151,574
Inventory impairment and other	74,800	84,000	$ 70,000		84,000
Other nonoperating income (expense)					(91,550)	(110,414)	169,719
Deferred purchase price receivable	0				0
Asset-backed Securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Transferor's interests in transferred financial assets	292,500				292,500
Elementum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gain on deconsolidation							151,600
Derecognized cash							72,600
Additional impairment charges	38,000
Unrelated Third-Party Company
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Gain on deconsolidation						76,000
Bright Machines
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investments in non-consolidated companies				$ 127,600
Gain on deconsolidation						87,000
Finance lease, right-of-use asset	25,400	30,300			25,400	30,300
Finance lease, liability	22,800	34,800			22,800	34,800
Transfer of employees and equipment, net book value				$ 35,000
Capital lease obligation	$ 22,806	$ 34,828			22,806	$ 34,828	$ 0
Business combination, consideration transferred					44,000
Other nonoperating income (expense)					$ (23,000)