Summary of Significant Accounting Policies Summary of Significant Accounting Policies (Narrative) (Details) $ / shares in Units, shares in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) shares	Dec. 31, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)
Organization Consolidation And Presentation [Line Items]
Cash equivalents		$ 4,400,000	$ 4,400,000	$ 4,400,000	$ 4,400,000	$ 4,400,000	$ 146,100,000
Revenue recognized for performance obligations satisfied over time				30.00%
Selling, general and administrative expenses			727,601,000				680,273,000	$ 619,546,000
Depreciation expense			41,208,000				39,627,000	43,022,000
Number of reportable segments				1		1
Number of operating segments				5
Amount authorized for share repurchase program		75,000,000.0	75,000,000.0	$ 75,000,000.0	75,000,000.0	$ 75,000,000.0
Repurchases of common stock under share repurchase program			(16,446,000)				(2,891,000)
Amount remaining under repurchase program		55,700,000	55,700,000	55,700,000	55,700,000	55,700,000
Aggregate maximum obligation of reinsurer								17,500,000
Insurance reserves related to reinsurance claims		2,500,000	2,500,000	2,500,000	2,500,000	2,500,000	3,700,000
Debt issuance cost		5,900,000	5,900,000	5,900,000	5,900,000	5,900,000	6,400,000
Amortization of debt issuance costs			1,441,000				1,684,000	1,684,000
Deferred Tax Benefit, 2017 Tax Act							500,000	3,600,000
Operating lease liability		146,979,000	146,979,000	146,979,000	146,979,000	146,979,000			$ 115,000,000
Current portion of operating lease liabilities		26,147,000	26,147,000	26,147,000	26,147,000	26,147,000	0
Operating lease right-of-use assets		139,907,000	139,907,000	139,907,000	139,907,000	139,907,000	0		$ 110,000,000
Shipping and Handling [Member]
Organization Consolidation And Presentation [Line Items]
Selling, general and administrative expenses			200,800,000				189,600,000	172,200,000
Depreciation expense			25,200,000				22,900,000	24,800,000
Selling, general and administrative expenses [Member]
Organization Consolidation And Presentation [Line Items]
Retirement savings expense recorded			11,200,000				5,900,000	5,200,000
Advertising expense			6,000,000.0				4,900,000	5,800,000
Interest expense [Member]
Organization Consolidation And Presentation [Line Items]
Amortization of debt issuance costs			1,400,000				1,700,000	$ 1,700,000
Prepaid expenses and other current assets [Member]
Organization Consolidation And Presentation [Line Items]
Rebates receivable		20,800,000	20,800,000	20,800,000	20,800,000	20,800,000	18,000,000.0
Other long-term assets [Member]
Organization Consolidation And Presentation [Line Items]
Assets held for sale		0	0	0	0	0	1,300,000
Accounts payable [Member]
Organization Consolidation And Presentation [Line Items]
Book overdrafts		(2,500,000)	(2,500,000)	(2,500,000)	(2,500,000)	(2,500,000)	(100,000)
Accrued expenses and other liabilities [Member]
Organization Consolidation And Presentation [Line Items]
Warranty liabilities		$ 2,300,000	2,300,000	$ 2,300,000	$ 2,300,000	$ 2,300,000	$ 2,900,000
FY18 Repurchase Program 75M [Member]
Organization Consolidation And Presentation [Line Items]
Shares repurchased (shares) | shares		1.0					0.2
Weighted average price | $ / shares					$ 17.11		$ 15.91
Bad Debt Reserve [Member] | Selling, general and administrative expenses [Member]
Organization Consolidation And Presentation [Line Items]
Prior period misstatement	$ 4,300,000		$ 4,300,000