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Revenues Revenue Recognition (Details)
$ in Millions
12 Months Ended
Dec. 31, 2019
USD ($)
Distribution
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Customer Rebates and Allowances $ 49.4 $ 52.1  
Building Materials Distribution [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Number of Primary Distribution Methods | Distribution 2    
Building Materials Distribution [Member] | Shipping and Handling [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Cost of Goods and Services Sold $ 169.2 $ 156.5 $ 139.4