Commitments and Contingencies (Piedmont) (Narrative) (Details) - Piedmont, Florida [Member] - USD ($) $ in Millions |
6 Months Ended | 12 Months Ended |
---|---|---|
Mar. 31, 2016 |
Sep. 30, 2008 |
|
Loss Contingencies [Line Items] | ||
Accrual for environmental loss contingencies | $ 18.0 | $ 24.0 |
Years to complete environmental remediation | until 2019 to complete source area remediation with groundwater recovery and treatment, continuing through 2029 | |
Change in estimated exposure | $ 0.0 | |
Segment Discontinued Operations Member | ||
Loss Contingencies [Line Items] | ||
Pretax environmental expense | $ 24.0 |