Segment and Related Information - Depreciation and Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Depreciation and Amortization Expense
Depreciation and amortization expense	$ 251	$ 794	$ 2,675	$ 1,585
Operating segment | Project Management
Depreciation and Amortization Expense
Depreciation and amortization expense	304	790	668	1,564
Corporate
Depreciation and Amortization Expense
Depreciation and amortization expense	(53)	$ 4	2,007	$ 21
Leasehold Improvements | Corporate
Depreciation and Amortization Expense
Depreciation and amortization expense	$ 278		$ 1,582