Acquisitions, Goodwill And Other Intangible Assets (Schedule Of Business Acquisitions) (Details) - USD ($) $ in Thousands	1 Months Ended			3 Months Ended		12 Months Ended
	Jan. 31, 2020	Dec. 31, 2019	Aug. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Cash consideration, net of cash acquired				$ 95,766	$ 0
Goodwill		$ 351,114		399,360		$ 351,114
Measurement Period Adjustments
Goodwill (not tax deductible)				12,027
Polyplastic
Business Acquisition [Line Items]
Cash consideration, net of cash acquired	$ 95,766
Contingent consideration	2,796
Total fair value of consideration given	98,562
Identifiable intangible assets	53,674
Net tangible assets	7,234
Total fair value of net assets acquired	60,908
Goodwill	$ 37,654
CURT
Business Acquisition [Line Items]
Cash consideration, net of cash acquired		337,640		337,640
Accounts receivable		28,611		28,611		28,611
Inventories		88,765		82,117		88,765
Fixed assets		24,036		24,036		24,036
Operating lease right-of-use assets		27,925		27,925		27,925
Other tangible assets		4,060		3,563		4,060
Accounts payable		(18,577)		(18,577)		(18,577)
Current portion of operating lease obligations		(5,360)		(5,360)		(5,360)
Accrued expenses and other current liabilities		(10,002)		(10,002)		(10,002)
Operating lease obligations		(22,565)		(22,565)		(22,565)
Deferred taxes		(31,877)		(30,125)		(31,877)
Total fair value of net assets acquired		234,721		221,228		234,721
Goodwill		102,919		116,412		102,919
Measurement Period Adjustments
Inventories				(6,648)
Other tangible assets				(497)
Deferred taxes				1,752
Total fair value of net assets acquired				(13,493)
Goodwill (not tax deductible)				13,493
CURT | Customer Relationships
Business Acquisition [Line Items]
Identifiable intangible assets		112,000		104,200		112,000
Measurement Period Adjustments
Intangible assets				(7,800)
CURT | Tradenames
Business Acquisition [Line Items]
Identifiable intangible assets		37,705		37,405		37,705
Measurement Period Adjustments
Intangible assets				(300)
Lewmar Marine Limited
Business Acquisition [Line Items]
Cash consideration, net of cash acquired				43,224		43,224
Total fair value of consideration given			$ 43,200
Identifiable intangible assets		19,580		21,750		19,580
Net tangible assets		3,286		2,581		3,286
Total fair value of net assets acquired		22,866		24,331		22,866
Goodwill		$ 20,358		18,893		$ 20,358
Measurement Period Adjustments
Intangible assets				2,170
Other tangible assets				(705)
Total fair value of net assets acquired				1,465
Goodwill (not tax deductible)				$ (1,465)