Commitments And Contingencies (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	Jul. 31, 2015	Jun. 30, 2015
Commitments And Contingencies [Line Items]
Expected revenue		$ 205.0
Maximum liability for damages		82.0
Performance bond issued		60.0
Surety Bond [Member]
Commitments And Contingencies [Line Items]
Values associated with surety arrangements		304.2
Amount exposed to bond		$ 81.8
Minimum [Member]
Commitments And Contingencies [Line Items]
Cost basis of component parts as a percentage of revenues		5.00%
Maximum liability for damages		$ 24.0
Maximum [Member]
Commitments And Contingencies [Line Items]
Cost basis of component parts as a percentage of revenues		10.00%
Maximum liability for damages		$ 34.0
Subsequent Event [Member]
Commitments And Contingencies [Line Items]
Additional bond amount	$ 85.0
Utility-Scale Solar Project [Member]
Commitments And Contingencies [Line Items]
Surety bond issued		$ 120.0
Warranty period		3 years