Business Divestiture - Assets and Liabilities (Details) - Operations and maintenance - Disposal Group, Disposed of by Sale, Not Discontinued Operations $ in Thousands	Jun. 28, 2020 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accounts receivable	$ 5,693
Contract assets, current portion	3,239
Prepaid expenses, other current assets, and cash	4,786
Other long-term assets	634
Total assets	14,352
Accounts payable	3,434
Contract liabilities, current portion	4,204
Other current liabilities	808
Other long-term liabilities	2,245
Total liabilities	10,691
Net assets	$ 3,661