The following tables, which are reconciled to consolidated amounts, provide total revenues and gross profit (loss) by line of business: Building Materials (further divided by product line) and Magnesia Specialties. Interproduct revenues represent sales from the aggregates product line to the ready mixed concrete and asphalt and paving product lines and sales from the cement product line to the ready mixed concrete product line. Total revenues and gross profit (loss) reflect continuing operations only.


years ended December 31 (in millions) Total revenues	2023			2022			2021
Building Materials business:
Aggregates	$	4,301.6		$	3,879.0		$	3,344.3
Cement		725.5			620.0			509.3
Ready mixed concrete		1,009.3			953.2			1,147.5
Asphalt and paving		887.1			787.9			517.9
Less: interproduct revenues		(461.7	)		(383.4	)		(403.7	)
Total Building Materials business		6,461.8			5,856.7			5,115.3
Magnesia Specialties		315.4			304.0			298.7
Consolidated total revenues	$	6,777.2		$	6,160.7		$	5,414.0

years ended December 31 (in millions) Gross profit (loss)	2023			2022			2021
Building Materials business:
Aggregates	$	1,378.1		$	983.8		$	907.6
Cement		333.6			202.7			155.9
Ready mixed concrete		102.0			70.7			96.5
Asphalt and paving		109.0			81.0			79.9
Total Building Materials business		1,922.7			1,338.2			1,239.9
Magnesia Specialties:		97.1			90.9			106.5
Corporate		2.8			(5.8	)		2.0
Consolidated gross profit	$	2,022.6		$	1,423.3		$	1,348.4

Performance Obligations. Performance obligations are contractual promises to transfer or provide a distinct good or service for a stated price. The Company’s product sales agreements are single-performance obligations that are satisfied at a point in time. Performance obligations within paving service agreements are satisfied over time, primarily ranging from one day to two years. Customer payment terms are generally 30 days from invoice date. Customer payments for the paving operations are based on a contractual billing schedule and are due 30 days from invoice date.

Future revenues from unsatisfied performance obligations at December 31, 2023, 2022 and 2021 were $250.5 million, $239.2 million and $153.9 million, respectively, where the remaining periods to complete these obligations ranged from one month to 22 months at December 31, 2023, two months to 34 months at December 31, 2022 and three months to 12 months at December 31, 2021.

Service Revenues. Service revenues, which include paving operations located in California and Colorado, were $410.7 million, $353.7 million and $259.1 million for the years ended December 31, 2023, 2022 and 2021, respectively.

Contract Balances. Costs in excess of billings relate to the conditional right to consideration for completed contractual performance and are contract assets on the consolidated balance sheets. Costs in excess of billings are reclassified to accounts receivable when the right to consideration becomes unconditional. Billings in excess of costs relate to customers invoiced in advance of contractual performance and are contract liabilities on the consolidated balance sheets. The following table presents information about the Company’s contract balances:

Revenues recognized from the beginning balance of contract liabilities for the years ended December 31, 2023 and 2022 were $10.3 million and $7.7 million, respectively.

Retainage. Retainage, which primarily relates to the paving services, represents amounts that have been billed to customers but payment withheld until final acceptance of the performance obligation by the customer. Included in Other current assets on the Company’s consolidated balance sheets, retainage was $16.6 million and $13.4 million at December 31, 2023 and 2022, respectively.