Exit Activity Costs and Asset Impairments (Narrative) (Details) $ in Thousands		6 Months Ended	12 Months Ended
	Apr. 15, 2016 USD ($)	Jun. 30, 2017 facility	Dec. 31, 2016 USD ($) facility	Dec. 31, 2015 USD ($) facility	Dec. 31, 2014 USD ($)
Restructuring Cost and Reserve [Line Items]
Exit activity charges			$ 13,747	$ 3,123	$ 1,671
Restructuring impairment charges			7,530	8,504	208
Exit activity costs			$ 6,217	$ 1,418	2,126
Number of consolidated facilities to be closed | facility			7	4
Sale leaseback gain				$ 6,799	663
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal	$ 8,800
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Net of Tax	2,000
Net proceeds from sale of business	$ 8,300		$ 8,250	$ 0	$ 0
Forecast
Restructuring Cost and Reserve [Line Items]
Number of consolidated facilities to be closed | facility		5