CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash Flows from Operating Activities:
Net cash used in operating activities	$ (12,181)	$ (13,613)
Cash Flows from Investing Activities:
Proceeds from sales of and distributions from companies	99,324	14,912
Acquisitions of ownership interest in companies	(6,000)	(250)
Advances and loans to companies	(4,618)	(7,949)
Repayment of advances and loans to companies	0	10,500
Purchases of marketable securities	(57,243)	0
Proceeds from sales and maturities in marketable securities	70,189	3,771
Net cash provided by investing activities	101,652	20,984
Cash Flows from Financing Activities:
Repayments on credit facility	(24,024)	0
Proceeds from credit facility	0	35,000
Issuance costs of credit facility	0	(2,252)
Repurchase of convertible senior debentures	0	(41,000)
Tax withholdings related to equity-based awards	(180)	(200)
Repurchase of Company common stock	0	0
Net cash used in financing activities	(24,204)	(8,452)
Net change in cash, cash equivalents and restricted cash	65,267	(1,081)
Cash, cash equivalents and restricted cash at beginning of period	8,203	27,087
Cash, cash equivalents and restricted cash at end of period	$ 73,470	$ 26,006