Acquisitions, Goodwill And Other Intangible Assets (Schedule of Business Acquisitions) (Details) - USD ($) $ in Thousands	1 Months Ended			12 Months Ended
	Dec. 31, 2019	Nov. 30, 2019	Aug. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition
Cash consideration, net of cash acquired				$ 447,764	$ 184,792	$ 60,588
Assets Acquired
Operating lease right-of-use assets	$ 34,300			34,300
Liabilities Assumed
Goodwill	351,114			351,114	$ 180,168	$ 124,183
CURT
Business Acquisition
Cash consideration, net of cash acquired	337,640
Total value of consideration given	337,600
Assets Acquired
Accounts receivable	28,611			28,611
Inventories	88,765			88,765
Fixed assets	24,036			24,036
Operating lease right-of-use assets	27,925			27,925
Other tangible assets	4,060			4,060
Liabilities Assumed
Accounts payable	(18,577)			(18,577)
Current portion of operating lease obligations	(5,360)			(5,360)
Accrued expenses and other current liabilities	(10,002)			(10,002)
Operating lease obligations	(22,565)			(22,565)
Deferred taxes	(31,877)			(31,877)
Total fair value of net assets acquired	234,721			234,721
Goodwill	102,919			102,919
PWR-ARM
Business Acquisition
Cash consideration		$ 40,000
Holdback payment		5,000
Total value of consideration given		45,000
Assets Acquired
Identifiable intangible assets		7,030
Other tangible assets		520
Liabilities Assumed
Total fair value of net assets acquired		7,550
Goodwill		$ 37,450
Lewmar Marine Limited
Business Acquisition
Cash consideration, net of cash acquired			$ 43,224
Total value of consideration given			43,200
Assets Acquired
Identifiable intangible assets			19,579
Other tangible assets			3,287
Liabilities Assumed
Total fair value of net assets acquired			22,866
Goodwill			$ 20,358
Customer relationships | CURT
Assets Acquired
Identifiable intangible assets	112,000			112,000
Trade name | CURT
Assets Acquired
Identifiable intangible assets	$ 37,705			$ 37,705