Contingencies and Commitments (Details) $ in Millions					1 Months Ended			6 Months Ended	12 Months Ended
	Oct. 01, 2014 USD ($)	Mar. 20, 2014 USD ($)	Oct. 30, 2013 USD ($)	Aug. 20, 2013 USD ($)	Mar. 31, 2015 USD ($)	Mar. 31, 2011 USD ($)	Jun. 30, 2003 USD ($)	Jun. 30, 2017 USD ($) ft² claim	Dec. 31, 2009 USD ($) room	May 17, 2017 USD ($)	Jul. 31, 2014 USD ($)	May 31, 2012 USD ($)	Sep. 30, 2011 USD ($)	Jul. 31, 2010 USD ($)	May 31, 2010 USD ($)	Mar. 31, 2010 USD ($)	Jun. 30, 2009 USD ($)	Feb. 28, 2006 USD ($)
Long Island Expressway/Cross Island Parkway Matter [Member]
Loss Contingencies [Line Items]
Estimated value of project completed in Feb. 2006																		$ 130.0
Value of claim filed						$ 53.8
Amount receivable as per final agreement													$ 0.5
Value of counterclaim filed												$ 151.0
Fontainebleau Matter [Member]
Loss Contingencies [Line Items]
Number of rooms in hotel/casino complex | room									3,800
Amount of court order in favor of plaintiff															$ 45.0
Total outstanding liens on property, including subcontractors' liens																	$ 44.0
Amount set aside from approved sale for distribution to satisfy creditor claims														$ 125.0
Estimated sustainable lien amount														$ 350.0
Honeywell Street/Queens Boulevard Bridges Matter [Member]
Loss Contingencies [Line Items]
Value of claim filed							$ 8.8
Value of counterclaim filed																$ 74.6
Release of retention plus interest								$ 1.1
Westgate Planet Hollywood Matter [Member]
Loss Contingencies [Line Items]
Settlement receipt		$ 0.6
Total awards		19.7
Damages awarded which were anticipated to be paid including interest		$ 3.1
Value of cross complaint filed									$ 51.0
Value of counterclaim filed									45.0
Total outstanding liens on property, including subcontractors' liens									23.2
Value of mechanic's lien release bond									$ 22.3		$ 22.3
Value of supersedeas bond											1.7
Total value of security											$ 24.0
U.S. Department of Commerce, National Oceanic and Atmospheric Administration Matter [Member]
Loss Contingencies [Line Items]
Total awards					$ 1.0
Value of claim filed	$ 0.7		$ 2.6	$ 26.8
Number of claims | claim								3
Square footage of facility | ft²								287,000
Total awards denied					$ 29.5
Minimum [Member[ | Westgate Planet Hollywood Matter [Member]
Loss Contingencies [Line Items]
Total value of security										$ 20.0