New Financial Accounting Pronouncements - Additional Information (Detail) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2018 USD ($) Divestiture	Sep. 30, 2018 Obligation	Dec. 31, 2017	Dec. 31, 2016 USD ($)
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
U.S. federal corporate statutory tax rate		21.00%	35.00%
Cash equivalents and restricted cash, original maturities of highly liquid investments		3 months
ASU 2016-15 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification of certain cash receipts and payments from financing activities to investing activities				$ 1.0
ASU 2014-09 [Member] | Energy Solutions and Industrial Solutions Segments [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue performance obligation, description of timing		The typical life of our contracts is generally less than 12 months and each contract generally contains only one performance obligation, to provide goods or services to the customer.
Number of performance obligation | Obligation		1
ASU 2014-09 [Member] | Maximum [Member] | Energy Solutions and Industrial Solutions Segments [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Contracts life		12 months
ASU 2018-02 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Decrease in Accumulated loss	$ 1.2
Increase in accumulated other comprehensive loss	$ 1.2
ASU 2017-01 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Number of divestitures | Divestiture	2