Additional Balance Sheet and Cash Flow Information (Inventories, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Inventory [Line Items]
Raw materials and work in process	$ 161,664	$ 140,639
Inventory at lower of FIFO cost or net realizable value	590,557	548,184
Excess of FIFO over LIFO cost	(52,355)	(48,267)
Total inventories, net	538,202	499,917
Obsolescence reserves deducted from FIFO cost	38,700	39,900
Motorcycles
Inventory [Line Items]
Inventory, finished goods, net of inventory valuation adjustment	289,530	285,281
Parts And Accessories And General Merchandise
Inventory [Line Items]
Inventory, finished goods, net of inventory valuation adjustment	$ 139,363	$ 122,264