Summary of Significant Accounting Policies - Revenue Recognition (Details)	12 Months Ended
	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Payment discount	1.00%
Payment discount days available	20 days
Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Collection terms	45 days
Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Collection terms	55 days
International
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Extended collection terms	120 days
Fine Paper And Packaging | Minimum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Collection terms	20 days
Payment discount	0.00%
Fine Paper And Packaging | Maximum
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Collection terms	30 days
Payment discount	2.00%