XML 52 R42.htm IDEA: XBRL DOCUMENT v3.19.1
Description of the Business and Summary of Significant Accounting Policies - Non-trade Receivables (Details) - USD ($)
$ in Millions
Mar. 31, 2019
Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]    
Non-trade receivables $ 10.3 $ 46.2