SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details - Investment in Joint Ventures) - 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
Accounting Policies [Abstract]
Beginning balance				$ 52,435				$ 43,509	$ 52,435	$ 43,509
Equity contributions in existing and purchase of interest in joint ventures									2,000	4,062
Equity in earnings in these joint ventures	$ 1,830	$ 2,822	$ 3,748	$ 2,977	$ 5,182	$ 3,450	$ 2,994	$ 1,928	11,377	13,554	$ 9,767
Disposition of equity method interest upon acquisition of control in NJIN									(2,993)
Distribution of earnings									(24,846)	(8,690)	(2,926)
Ending balance	$ 37,973				$ 52,435				$ 37,973	$ 52,435	$ 43,509