CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ (8.4)	$ 31.1	$ 64.5
Other Comprehensive Income (Loss), net of tax:
Unrealized interest rate hedging gain	2.6	0.0	0.0
Reclassification adjustment for interest expense included in net loss	0.4	0.0	0.0
Defined benefit pension plans:
Actuarial loss	(4.6)	(7.1)	(26.7)
Amortization of net loss included in net periodic pension cost	7.5	7.3	4.5
Amortization of prior service credit included in net periodic pension cost	(0.9)	(1.3)	(1.3)
Curtailment	(1.5)	0.0	0.0
Prior service cost	0.0	(0.4)	0.0
Income taxes related to other comprehensive income	(1.4)	0.6	9.2
Other Comprehensive Income (Loss)	2.1	(0.9)	(14.3)
Comprehensive Income	(6.3)	30.2	50.2
Comprehensive income attributable to noncontrolling interest	(1.8)	(1.5)	(3.1)
Comprehensive income (loss) attributable to A&B	$ (8.1)	$ 28.7	$ 47.1