Organization and Business Operations - IPO (Details) - USD ($) $ / shares in Units, $ in Millions		3 Months Ended
	Aug. 16, 2017	Mar. 31, 2017
Initial Public Offering
Repayments of long-term debt	$ 10.4	$ 0.8
Payment of cash bonuses to certain employees	0.7
ESCO
Initial Public Offering
Cash consideration	45.2
IPO
Initial Public Offering
Net proceeds from initial public offering	$ 20.7
Class A Common Stock | ESCO
Initial Public Offering
Share price (in dollars per share)	$ 14.50
Class A Common Stock | IPO
Initial Public Offering
Stock issued (in shares)	5,862,069
Share price (in dollars per share)	$ 14.50
Gross proceeds from initial public offering	$ 85.0
Net proceeds from initial public offering	77.0
Underwriting discounts and commissions	4.2
Net proceeds from the initial public offering, after repayment of debt, funding of acquisition and other costs	$ 3.9