Acquisitions - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed on Preliminary Purchase Price Allocation (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Jul. 31, 2019	Jan. 07, 2019
Business Acquisition [Line Items]
Contract assets	$ 626,513	$ 575,089
Goodwill	1,044,014	1,047,425
Contract liabilities	$ (241,178)	$ (230,681)
OGSystems
Business Acquisition [Line Items]
Cash and cash equivalents				$ 5,772
Accounts receivable				9,904
Contract assets				9,747
Prepaid expenses and other current assets				4,307
Property and equipment				4,085
Right of use assets, operating leases				8,826
Goodwill				183,540
Intangible assets				92,300
Other noncurrent assets				10
Accounts payable				(5,450)
Accrued expenses and other current liabilities				(7,147)
Contract liabilities				(1,300)
Short-term lease liabilities, operating leases				(805)
Income tax payable				(1,178)
Deferred tax liabilities				(1,195)
Long-term lease liabilities, operating leases				(8,021)
Other long-term liabilities				(1,015)
Net assets acquired				$ 292,380
QRC Technologies
Business Acquisition [Line Items]
Cash and cash equivalents			$ 5,925
Accounts receivable			5,587
Prepaid expenses and other current assets			5,727
Property and equipment			1,205
Right of use assets, operating leases			5,228
Goodwill			125,091
Intangible assets			76,200
Accounts payable			(1,567)
Accrued expenses and other current liabilities			(4,025)
Short-term lease liabilities, operating leases			(545)
Long-term lease liabilities, operating leases			(4,683)
Net assets acquired			$ 214,143