INVESTMENTS - Summary of Investments in Nonconsolidated Affiliates and Available-for-sale Securities (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments in and Advances to Affiliates, at Fair Value
Beginning balance				$ 118,507				$ 87,990	$ 118,507	$ 87,990
Cash contributions									1,051	2,248
Acquisitions									23,358	35,523
Equity in loss	$ 729	$ 172	$ (38)	157	$ (615)	$ (2,238)	$ 240	(242)	1,020	(2,855)	$ (16,733)
Disposals									(29,587)	(816)
Foreign currency translation adjustment									(352)	768
Distributions received									(2,500)	(775)
Impairment of investments									(16,434)	(4,873)
Unrealized holding loss on marketable securities									3,818	(414)
Other										1,711
Ending balance	98,881				118,507				98,881	118,507	87,990
Notes Receivable
Investments in and Advances to Affiliates, at Fair Value
Beginning balance				13,792				132	13,792	132
Cash contributions									0	0
Acquisitions									15,076	13,602
Equity in loss									0	0
Disposals									(728)	(188)
Foreign currency translation adjustment									0	0
Distributions received									0	0
Impairment of investments									(2,064)	(671)
Unrealized holding loss on marketable securities									0	0
Other										917
Ending balance	26,076				13,792				26,076	13,792	132
Equity Method Investments
Investments in and Advances to Affiliates, at Fair Value
Beginning balance				24,395				14,477	24,395	14,477
Cash contributions									1,051	2,248
Acquisitions									3,732	10,361
Equity in loss									1,020	(2,855)
Disposals									(33)	0
Foreign currency translation adjustment									(29)	145
Distributions received									(2,500)	(775)
Impairment of investments									0	0
Unrealized holding loss on marketable securities									0	0
Other										794
Ending balance	27,636				24,395				27,636	24,395	14,477
Other Investments
Investments in and Advances to Affiliates, at Fair Value
Beginning balance				78,776				71,666	78,776	71,666
Cash contributions									0	0
Acquisitions									4,550	11,560
Equity in loss									0	0
Disposals									(28,826)	(628)
Foreign currency translation adjustment									(256)	380
Distributions received									0	0
Impairment of investments									(14,370)	(4,202)
Unrealized holding loss on marketable securities									4,389	0
Other										0
Ending balance	44,263				78,776				44,263	78,776	71,666
Marketable Equity Securities
Investments in and Advances to Affiliates, at Fair Value
Beginning balance				$ 1,544				$ 1,715	1,544	1,715
Cash contributions									0	0
Acquisitions									0	0
Equity in loss									0	0
Disposals									0	0
Foreign currency translation adjustment									(67)	243
Distributions received									0	0
Impairment of investments									0	0
Unrealized holding loss on marketable securities									(571)	(414)
Other										0
Ending balance	$ 906				$ 1,544				$ 906	$ 1,544	$ 1,715