Revenue

3 Months Ended

Mar. 31, 2022

Revenue From Contract With Customer [Abstract]

Revenue

2. Revenue

The following table disaggregates our sales by product category (in thousands):

	Three Months Ended March 31,
	2022		2021
	(in thousands)
Lumber & lumber sheet goods	$	2,325,355	$	1,769,299
Manufactured products		1,354,587		860,913
Windows, doors & millwork		1,011,572		736,156
Specialty building products & services		989,617		807,407
Net sales	$	5,681,131	$	4,173,775

Net sales from installation and construction services were less than 10% of the Company’s net sales for each period presented.

The timing of revenue recognition, invoicing and cash collection results in accounts receivable, unbilled receivables, contract assets and contract liabilities. Contract assets include unbilled amounts when the revenue recognized exceeds the amount billed to the customer, and amounts representing a right to payment from previous performance that is conditional on something other than passage of time, such as retainage. Contract liabilities consist of deferred revenue and customer advances and deposits.

For the three months ended March 31, 2022 and 2021, we recognized as revenue approximately 70% and 78% of the contract liabilities balance at December 31, 2021 and 2020, respectively.