INVESTMENTS - Summary of Investments in Nonconsolidated Affiliates and Available-for-sale Securities (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Investments in and Advances to Affiliates, at Fair Value
Beginning balance				$ 87,990				$ 88,994	$ 87,990	$ 88,994
Cash advances									2,248	2,993
Acquisitions									35,523	34,534
Equity in loss	$ (615)	$ (2,238)	$ 240	(242)	$ (15,807)	$ 1,117	$ (1,610)	(433)	(2,855)	(16,733)	$ (902)
Disposals									(816)	(3,552)
Foreign currency transaction adjustment									768	(276)
Distributions received									(775)	(3,709)
Impairment of investments									(4,873)	(14,798)
Unrealized holding loss on marketable securities									(414)	(576)
Other									1,711	1,113
Ending balance	118,507				87,990				118,507	87,990	88,994
Notes Receivable
Investments in and Advances to Affiliates, at Fair Value
Beginning balance				132				156	132	156
Cash advances									0	0
Acquisitions									13,602	917
Equity in loss									0	0
Disposals									(188)	(76)
Foreign currency transaction adjustment									0	0
Distributions received									0	0
Impairment of investments									(671)	0
Unrealized holding loss on marketable securities									0	0
Other									917	(865)
Ending balance	13,792				132				13,792	132	156
Equity Method Investments
Investments in and Advances to Affiliates, at Fair Value
Beginning balance				14,477				27,710	14,477	27,710
Cash advances									2,248	2,993
Acquisitions									10,361	7,531
Equity in loss									(2,855)	(16,733)
Disposals									0	(2,476)
Foreign currency transaction adjustment									145	(45)
Distributions received									(775)	(3,709)
Impairment of investments									0	0
Unrealized holding loss on marketable securities									0	0
Other									794	(794)
Ending balance	24,395				14,477				24,395	14,477	27,710
Cost Method Investments
Investments in and Advances to Affiliates, at Fair Value
Beginning balance				71,666				58,802	71,666	58,802
Cash advances									0	0
Acquisitions									11,560	26,086
Equity in loss									0	0
Disposals									(628)	(1,000)
Foreign currency transaction adjustment									380	(196)
Distributions received									0	0
Impairment of investments									(4,202)	(14,798)
Unrealized holding loss on marketable securities									0	0
Other									0	2,772
Ending balance	78,776				71,666				78,776	71,666	58,802
Marketable Equity Securities
Investments in and Advances to Affiliates, at Fair Value
Beginning balance				$ 1,715				$ 2,326	1,715	2,326
Cash advances									0	0
Acquisitions									0	0
Equity in loss									0	0
Disposals									0	0
Foreign currency transaction adjustment									243	(35)
Distributions received									0	0
Impairment of investments									0	0
Unrealized holding loss on marketable securities									(414)	(576)
Other									0	0
Ending balance	$ 1,544				$ 1,715				$ 1,544	$ 1,715	$ 2,326