Investments - Schedule of Investments (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2020 USD ($)
Equity Method Investment Balances [Roll Forward]
Investment in joint ventures at beginning of the period	$ 57,936
Earnings from joint ventures	1,155
Foreign currency translation adjustment	(226)
Investment in joint ventures at end of the period	58,865
WMES
Equity Method Investment Balances [Roll Forward]
Investment in joint ventures at beginning of the period	44,134
Earnings from joint ventures	920
Foreign currency translation adjustment	0
Investment in joint ventures at end of the period	45,054
CASC Willis
Equity Method Investment Balances [Roll Forward]
Investment in joint ventures at beginning of the period	13,802
Earnings from joint ventures	235
Foreign currency translation adjustment	(226)
Investment in joint ventures at end of the period	$ 13,811