Business Combination (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Jun. 30, 2015	Apr. 15, 2016	Sep. 30, 2015
Business Acquisition [Line Items]
Cash Paid for Acquisition		$ 59,698	$ 3,112
Contingent Consideration Fair Value	$ 780	780
Amount From Credit Facility Used For Acquisitions		$ 20,000
Interest Rate During Period		2.50%
Goodwill Written Off Related To Sale Of Business Unit		$ 577
Assets held for sale	0	0			$ 0
Infrastructure Solutions [Member]
Business Acquisition [Line Items]
Goodwill Written Off Related To Sale Of Business Unit		577
Loss on Sale of Assets From Divestiture		828
Assets held for sale				$ 2,200
Acquisition Related Costs [Member]
Business Acquisition Pro Forma Information Nonrecurring Adjustment [Line Items]
Business Combination Acquisition Related Costs		$ 681
Business Acquisitions
Business Acquisition [Line Items]
Number Of Businesses Acquired		4
Total Consideration Transferred		$ 59,583
Cash Purchase Consideration		59,298
Cash Paid for Acquisition		58,448
Additional Consideration To Be Paid		850
Revenues From Acquisitions	10,649	19,613
Operating Income From Acquisitions	1,193	$ 1,841
Business Acquisition Southern Rewind [Member] | Infrastructure Solutions [Member]
Business Acquisition [Line Items]
Name of Acquired Business		Southern Industrial Sales and Services, Inc. (“Southern Rewinding”)
Description of Acquired Business		a Columbus, Georgia-based motor repair and related field services company
Date of Acquisition Agreement			May 21, 2015
Total Consideration Transferred			$ 3,937
Cash Purchase Consideration			3,137
Cash Paid for Acquisition		$ 400
Additional Consideration To Be Paid		$ 400	800
Working Capital Transfer			$ 1,065
Business Acquisition Technibus [Member] | Infrastructure Solutions [Member]
Business Acquisition [Line Items]
Name of Acquired Business		Technibus Inc (“Technibus”)
Description of Acquired Business		a Canton, Ohio based provider of custom engineered, metal enclosed bus duct solutions
Date of Acquisition Agreement		Jun. 15, 2016
Goodwill Tax Basis	$ 15,218	$ 15,218
Business Acquisition STR [Member] | Commercial & Industrial [Member]
Business Acquisition [Line Items]
Name of Acquired Business		An 80% interest in STR Mechanical, LLC (“STR”)
Description of Acquired Business		An 80% interest in a Charlotte, North Carolina-based provider of commercial and industrial mechanical services, including maintenance, repair, and replacement services, and temperature control system installations
Minority Interest Ownership Percentage By Parent	80.00%	80.00%
Date of Acquisition Agreement		Apr. 27, 2016
Business Acquisition Calumet [Member] | Infrastructure Solutions [Member]
Business Acquisition [Line Items]
Name of Acquired Business		Calumet Armature & Electric, LLC (“Calumet”)
Description of Acquired Business		an Illinois-based provider of design, manufacturing, assembly, and repair services of electric motors for the industrial and mass transit markets
Date of Acquisition Agreement		Oct. 30, 2015
Minimum Contingent Consideration Value	$ 448	$ 448
Contingent Consideration Fair Value	780	780
Maximum Contingent Consideration Value	$ 2,250	$ 2,250
Business Acquisition Shanahan [Member] | Commercial & Industrial [Member]
Business Acquisition [Line Items]
Name of Acquired Business		Shanahan Mechanical and Electrical, Inc. (“Shanahan”)
Description of Acquired Business		a Nebraska-based provider of mechanical and electrical contracting services
Date of Acquisition Agreement		Nov. 20, 2015