Quarterly report pursuant to Section 13 or 15(d)

Revenue from Contracts with Customers - Contract Assets and Liabilities (Details)

v3.19.2
Revenue from Contracts with Customers - Contract Assets and Liabilities (Details) - USD ($)
$ in Thousands
Jun. 30, 2019
Dec. 31, 2018
Contract with Customer, Asset and Liability [Abstract]    
Contract assets $ 0 $ 0
Contract liabilities $ 9,000 $ 0