Business Segments - Schedule of Revenues by Major Customers (Detail) - Total revenue - Customer concentration risk	3 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
INOX Wind Limited
Segment Reporting Asset Reconciling Item [Line Items]
Concentration risk, revenue (less than 10% for Essential Energy and Reed & Reed Inc. for the three months ended June 2017)	22.00%	27.00%
U.S. Navy
Segment Reporting Asset Reconciling Item [Line Items]
Concentration risk, revenue (less than 10% for Essential Energy and Reed & Reed Inc. for the three months ended June 2017)	35.00%	0.00%
Reed & Reed Inc.
Segment Reporting Asset Reconciling Item [Line Items]
Concentration risk, revenue (less than 10% for Essential Energy and Reed & Reed Inc. for the three months ended June 2017)	10.00%	17.00%
Essential Energy
Segment Reporting Asset Reconciling Item [Line Items]
Concentration risk, revenue (less than 10% for Essential Energy and Reed & Reed Inc. for the three months ended June 2017)	10.00%	13.00%
XJ Group Corporation
Segment Reporting Asset Reconciling Item [Line Items]
Concentration risk, revenue (less than 10% for Essential Energy and Reed & Reed Inc. for the three months ended June 2017)	0.00%	12.00%