- Summary Of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Summary Of Significant Accounting Policies [Line Items]
Escrow Deposit	$ 16,300
Capitalized computer software, net	43,600	$ 46,900
Software amortization	9,300	9,500
Contract with customer, liability	49,500	44,200
Distribution, selling and administrative expenses	1,023,065	$ 952,865
Operating lease assets	$ 142,219
Maximum
Summary Of Significant Accounting Policies [Line Items]
Lessee, Operating Lease, Term of Contract	12 months
Customer Relationships
Summary Of Significant Accounting Policies [Line Items]
Intangible assets useful life (in years)	10 years	10 years
Customer Relationships | Minimum
Summary Of Significant Accounting Policies [Line Items]
Intangible assets useful life (in years)	3 years
Customer Relationships | Maximum
Summary Of Significant Accounting Policies [Line Items]
Intangible assets useful life (in years)	15 years
Other Intangibles
Summary Of Significant Accounting Policies [Line Items]
Intangible assets useful life (in years)	8 years	8 years
Other Intangibles | Minimum
Summary Of Significant Accounting Policies [Line Items]
Intangible assets useful life (in years)	1 year
Other Intangibles | Maximum
Summary Of Significant Accounting Policies [Line Items]
Intangible assets useful life (in years)	15 years
Software technology | Minimum
Summary Of Significant Accounting Policies [Line Items]
Computer software, useful life	3 years
Software technology | Maximum
Summary Of Significant Accounting Policies [Line Items]
Computer software, useful life	10 years
Warehouse equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life (in years)	3 years
Warehouse equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life (in years)	15 years
Buildings and leasehold improvements | Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life (in years)	5 years
Buildings and leasehold improvements | Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life (in years)	40 years
Computer equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life (in years)	15 years
Furniture and fixtures | Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life (in years)	3 years
Furniture and fixtures | Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life (in years)	8 years
Office equipment and other | Minimum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life (in years)	3 years
Office equipment and other | Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment useful life (in years)	8 years
Warehouse Facilities | Minimum
Summary Of Significant Accounting Policies [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Warehouse Facilities | Maximum
Summary Of Significant Accounting Policies [Line Items]
Lessee, Operating Lease, Term of Contract	10 years
Transportation And Material Handling Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Lessor, Operating Lease, Term of Contract	3 years
Transportation And Material Handling Equipment | Maximum
Summary Of Significant Accounting Policies [Line Items]
Lessor, Operating Lease, Term of Contract	10 years
Shipping and Handling
Summary Of Significant Accounting Policies [Line Items]
Distribution, selling and administrative expenses	$ 422,300	$ 563,400
Accounting Standards Update 2016-02
Summary Of Significant Accounting Policies [Line Items]
Operating lease assets			$ 197,000
Accounting Standards Update 2016-02 | Minimum
Summary Of Significant Accounting Policies [Line Items]
Operating lease assets			285,000
Accounting Standards Update 2016-02 | Maximum
Summary Of Significant Accounting Policies [Line Items]
Operating lease assets			$ 355,000