Other Non-Operating Income (Details 1) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Other Nonoperating Income (Expense) [Abstract]
Gain on acquiring a controlling interest in an equity affiliate	$ 3,708		$ 0		$ 3,708	$ 0
Foreign currency (loss) gain, net	(1,070)		109		3,220	623
Impairment of a cost method investment	0	$ (2,600)	0		(2,577)	0
Gain on cost method investments	2,571		0	$ 1,400	2,571	1,411
Gain on sale of a business	1,653		232		1,760	421
Gain on sale of equity affiliates	1,473		0		1,370	28,994
Gain on sale of a cost method investment	0		0		518	0
Other (loss) gain, net	(235)		887		218	(870)
Total Other Non-Operating Income	$ 8,100		$ 1,228		$ 10,788	$ 30,579