Uncompleted Contracts - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Sep. 30, 2014	Jun. 30, 2014
Customer Contracts [Line Items]
Contract Receivable Retainage, Due in Next Twelve Months	$ 29.7	$ 30.0
Contract Receivable Retainage, Due after Next Twelve Months	2.3	4.3
Change In Accounting Estimate, Financial Effect, Operating Income	3.3
Change in Accounting Estimate, Financial Effect, Net Income	1.3
S.M. Electric Company
Customer Contracts [Line Items]
Estimate of the remaining amount to be collected	0.7
Contract Receivable	$ 2.9