Long-Term Debt (Details) $ in Millions		1 Months Ended		12 Months Ended
	Aug. 16, 2017 USD ($) item	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 23, 2016 USD ($)	Dec. 31, 2015 USD ($)	Mar. 31, 2015 USD ($)	Feb. 28, 2015 USD ($)
Long-Term Debt
Current portion of long-term debt				$ (1.3)	$ (2.3)
Long-term debt, less current portion				5.8	9.8
Repayments of debt	$ 10.4			12.0	2.6
Credit facility
Long-Term Debt
Maximum borrowings				0.1
Maximum borrowing capacity				0.1
ESCO
Long-Term Debt
Secured Seller's Notes	7.0
Senior Revolving Credit Facility
Long-Term Debt
Maximum borrowings	$ 50.0
Percentage of eligible accounts receivable used in determining the borrowing base	85.00%
Current borrowing capacity	$ 21.9
Interest rate margin in event of default (as a percent)	2.00%
Fixed charge coverage ratio requirement	1.0
Liquidity requirement that is used in determining whether the Company has to maintain a certain fixed charge coverage ratio	$ 10.0
Time period in which the Company must maintain a certain level of liquidity	30 days
Amount of qualified cash the Company must have in determining whether the Company is subject to a fixed charge coverage ratio requirement	$ 20.0
Maximum borrowing capacity	50.0
Unamortized debt issuance costs	$ 0.7			0.7
Senior Revolving Credit Facility | Credit Facility Restrictions, clause (a)
Long-Term Debt
Measurement period of time used in the calculation of excess availability in determining any restrictions on the Company's ability to make distributions	90 days
Percentage used in the calculation of excess availability in determining any restrictions on the Company's ability to make distributions	22.50%
Amount used in the calculation of excess availability in determining any restrictions on the Company's ability to make distributions	$ 10.0
Senior Revolving Credit Facility | Credit Facility Restrictions, clause (b)
Long-Term Debt
Fixed charge ratio used in the calculation in determining any restrictions on the Company's ability to make distributions	1.0
Measurement period of time used in the calculation of excess availability in determining any restrictions on the Company's ability to make distributions	90 days
Percentage used in the calculation of excess availability in determining any restrictions on the Company's ability to make distributions	17.50%
Amount used in the calculation of excess availability in determining any restrictions on the Company's ability to make distributions	$ 7.0
Period of time from closing in determining when distributions can be made, if the threshold under clause (b) is met	12 months
Fixed charge coverage ratio used in determining when distributions can be made, if the threshold under clause (b) is met	1.0
Number of quarters the fixed charge coverage ratio is required to be maintained | item	2
Seller's Notes
Long-Term Debt
Face amount of debt	$ 7.0
Interest rate (as a percent)	5.00%
Seller's Note Due August 2018
Long-Term Debt
Face amount of debt	$ 1.2
Seller's Note Due February 2019
Long-Term Debt
Face amount of debt	$ 5.8
Term Loan
Long-Term Debt
Long-term debt					7.1
Other Long-Term Debt
Long-Term Debt
Long-term debt				7.0
Revolver
Long-Term Debt
Long-term debt				0.1	5.0
LIBOR Rate Loans | Senior Revolving Credit Facility
Long-Term Debt
Interest rate margin (as a percent)	1.50%
LIBOR Rate Loans | Senior Revolving Credit Facility | Minimum
Long-Term Debt
Interest rate margin (as a percent)	1.50%
LIBOR Rate Loans | Senior Revolving Credit Facility | Maximum
Long-Term Debt
Interest rate margin (as a percent)	2.00%
Base Rate Loans | Senior Revolving Credit Facility
Long-Term Debt
Interest rate margin (as a percent)	0.50%
Base Rate Loans | Senior Revolving Credit Facility | Minimum
Long-Term Debt
Interest rate margin (as a percent)	0.50%
Base Rate Loans | Senior Revolving Credit Facility | Maximum
Long-Term Debt
Interest rate margin (as a percent)	1.00%
Base Rate Loans | Senior Revolving Credit Facility | Federal Funds Rate
Long-Term Debt
Interest rate margin (as a percent)	0.50%
Base Rate Loans | Senior Revolving Credit Facility | LIBOR
Long-Term Debt
Interest rate margin (as a percent)	1.00%
Iberia Bank | Term Loan
Long-Term Debt
Long-term debt				0.0	6.2
Face amount of debt			$ 7.0
Number of monthly installments			60 months
Iberia Bank | Revolver
Long-Term Debt
Long-term debt					5.0
Maximum borrowings						$ 5.0	$ 2.0
Carrying value of assets used to secure debt					$ 107.9
Interest rate (as a percent)					4.12%
Maximum borrowing capacity						$ 5.0	$ 2.0
Texas Capital Bank | Term Loan
Long-Term Debt
Long-term debt				$ 0.0	$ 0.7
Maximum borrowings									$ 2.0
Carrying value of assets used to secure debt					$ 27.8
Interest rate (as a percent)					5.75%
Maximum borrowing capacity									$ 2.0
Benchmark Bank | Term Loan
Long-Term Debt
Long-term debt		$ 0.2			$ 0.2
Face amount of debt								$ 0.6
Carrying value of certificate of deposit used to secure debt		$ 0.2
Interest rate (as a percent)		4.50%
Repayments of debt		$ 0.4