Valuation and Qualifying Accounts (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Inventory obsolescence reserves	$ 7,194	$ 6,932
Inventory usage period	3 years
Inventory reserve percentage	100.00%
Product warranty accrual period of expenses used in calculation	12 months
Product warranty accrual period for sales used in calculation	12 months
Warranty	$ 4,992	5,335
Parts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Product warranty period	90 days
Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Product warranty accrual lag period	90 days
Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Product warranty accrual lag period	6 months
Maximum | Wholegoods
Accounts, Notes, Loans and Financing Receivable [Line Items]
Product warranty period	1 year
Reserve for sales discounts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Reserves for sales discounts on products shipped under promotional programs	$ 18,123	$ 15,652	$ 13,488	$ 15,094