SUPPLEMENTAL CASH FLOW INFORMATION - Supplemental Non-Cash Activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Noncash or Part Noncash Acquisitions [Line Items]
Interest	$ 40,773	$ 22,029
Taxes	9,463	19,774
Acquisition of iGo shares in exchange for Kasco equity	6,156	0
Exchange of debt securities for equity securities	0	3,317
Contingent purchase price (future earn-out) associated with the Dunmore acquisition	3,800	0
Common Units
Noncash or Part Noncash Acquisitions [Line Items]
Issuance of SPLP Units to purchase subsidiary shares from noncontrolling interests	3,159	0
Preferred Units
Noncash or Part Noncash Acquisitions [Line Items]
Issuance of SPLP Units to purchase subsidiary shares from noncontrolling interests	$ 3,812	$ 198,817