Investments - Short-term and Other Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Summary of Investment Holdings
Other investments	$ 287,683	$ 311,287
Related Parties
Summary of Investment Holdings
Other investments	235,843	238,841
Equity method investments
Summary of Investment Holdings
Other investments	140,897	143,511
Equity method investments | Related Parties
Summary of Investment Holdings
Other investments	105,839	109,612
Notes receivable
Summary of Investment Holdings
Other investments	130,067	129,299
Notes receivable | Related Parties
Summary of Investment Holdings
Other investments	130,004	129,229
Long-term Certificates of Deposit (CDs), at cost
Summary of Investment Holdings
Other investments	150	20,150
Investments, at fair value
Summary of Investment Holdings
Other investments	7,661	9,365
Investments, at cost or amortized cost
Summary of Investment Holdings
Other investments	$ 8,908	$ 8,962