Business Combination - Estimated Fair Value of Intangible Assets Acquired (Details) - USD ($) $ in Thousands		12 Months Ended
	Sep. 11, 2017	Dec. 31, 2017
Lightning Diversion Systems, Inc.
Business Acquisition [Line Items]
Intangible assets	$ 22,400
Customer relationships
Business Acquisition [Line Items]
Useful Life (In years)		17 years
Customer relationships | Lightning Diversion Systems, Inc.
Business Acquisition [Line Items]
Useful Life (In years)	15 years
Intangible assets	$ 21,100
Trade name
Business Acquisition [Line Items]
Useful Life (In years)		15 years
Trade name | Lightning Diversion Systems, Inc.
Business Acquisition [Line Items]
Useful Life (In years)	15 years
Intangible assets	$ 1,300