Revenue

6 Months Ended

Jun. 30, 2020

Revenue from Contract with Customer [Abstract]

Revenue

Revenue

Disaggregation of revenue

The following table shows net sales classified by major product category for the three and six months ended June 30, 2020 and 2019:

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2020		2019		2020		2019
Millwork, doors & windows	$	287,999	$	271,135	$	583,668	$	511,057
Structural components	164,535		166,955		324,879		308,231
Lumber & lumber sheet goods	292,817		281,855		551,956		523,814
Other building products & services	234,545		226,430		440,272		428,678
Total net sales	$	979,896	$	946,375	$	1,900,775	$	1,771,780

The following table reflects the Company’s estimate of net sales by each customer type for the three and six months ended June 30, 2020 and 2019:

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2020		2019		2020		2019
Single-family homebuilders	$	702,388	$	716,974	$	1,377,159	$	1,345,692
Remodeling contractors	127,699		110,313		232,368		198,521
Multi-family, commercial & other contractors	149,809		119,088		291,248		227,567
Total net sales	$	979,896	$	946,375	$	1,900,775	$	1,771,780

Net sales for the Company's building products contracts was $739.4 million, $712.4 million, $1,426.0 million and $1,333.3 million for the three and six months ended June 30, 2020 and 2019, respectively. Net sales for the Company's construction services contracts, which includes both products and installation services, was $240.5 million, $234.0 million, $474.7 million and $438.5 million for the three and six months ended June 30, 2020 and 2019, respectively.

Contract balances

The following table reflects the Company’s contract balances as of June 30, 2020 and December 31, 2019:

(in thousands)	June 30, 2020		December 31, 2019		Change
Receivables, including unbilled receivables presented in prepaid expenses and other current assets	$	375,822	$	333,044	$	42,778
Contract assets	33,871		32,125		1,746
Contract liabilities	$	42,610	$	31,094	$	11,516

During the six months ended June 30, 2020, the Company’s contract assets increased by $1.7 million and the Company’s contract liabilities increased by $11.5 million. The changes in contract assets and liabilities were primarily due to the timing of revenue recognition, as the balances were not materially impacted by any other factors. For the three and six months ended June 30, 2020, the Company recognized revenue of $3.4 million and $27.8 million, respectively, that was included in contract liabilities as of December 31, 2019. Revenue recognized related to performance obligations that were satisfied or partially satisfied in previous periods was not material for the three and six months ended June 30, 2020.

As permitted by ASC 606, Revenue from Contracts with Customers, the Company has elected not to disclose the value of unsatisfied performance obligations, as the Company’s contracts generally have an original expected length of one year or less.