Acquisitions - Unaudited Proforma Information (Details) - Boat Holdings, LLC - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Acquisition [Line Items]
Net sales	$ 1,779,315	$ 1,689,050	$ 3,275,005	$ 3,151,165
Net income	$ 89,346	$ 104,446	$ 138,526	$ 166,336
Basic earnings per share (in dollars per share)	$ 1.45	$ 1.65	$ 2.26	$ 2.63
Diluted earnings per common share (in dollars per share)	$ 1.44	$ 1.61	$ 2.23	$ 2.56