Acquisitions - Unaudited Proforma Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Boat Holdings, LLC
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net sales	$ 6,429,700	$ 5,980,741
Net income	$ 360,690	$ 182,749
Basic earnings per share (in dollars per share)	$ 5.77	$ 2.90
Diluted earnings per common share (in dollars per share)	$ 5.64	$ 2.85
TAP
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net sales			$ 5,161,688
Net income			$ 240,400
Basic earnings per share (in dollars per share)			$ 3,740
Diluted earnings per common share (in dollars per share)			$ 3,690