Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2023

Basis of Presentation

Restricted cash

Restricted cash — Restricted cash consists primarily of cash balances that are restricted as to withdrawal or usage and contract retention payments made by customers into escrow bank accounts and are included in prepaid expenses and other current assets in our Condensed Consolidated Balance Sheets. Escrow cash accounts are released to us by customers as projects are completed in accordance with contract terms. As a result of the PLH acquisition (as defined below), we acquired cash pledged to secure letters of credit, which is recorded as restricted cash at December 31, 2022. As of September 30, 2023 all of the restricted cash from the PLH acquisition had been released. The following tables provide a reconciliation of cash, cash equivalents and restricted cash reported within the Condensed Consolidated Balance Sheets to the totals of such amounts shown in the Condensed Consolidated Statements of Cash Flows (in thousands):

	September 30,
	2023		2022
Cash and cash equivalents	$	160,736	$	111,937
Restricted cash included in prepaid expenses and other current assets		5,810		21,089
Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	$	166,546	$	133,026

	December 31,
	2022		2021
Cash and cash equivalents	$	248,692	$	200,512
Restricted cash included in prepaid expense and other current assets		10,299		5,131
Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	$	258,991	$	205,643

Accounts Receivable Securitization Facility

Accounts Receivable Securitization Facility — In June 2023, we entered into an Accounts Receivable Securitization Facility (“the Facility”) with PNC Bank, National Association ("PNC") to improve cash flows from trade accounts receivable. The Facility has a one-year term, and the maximum purchase commitment by PNC is $100.0 million, at any one time.

Under the Facility, certain of our designated subsidiaries may sell their trade accounts receivable as they are originated to a wholly owned bankruptcy remote Special Purpose Entity (“SPE”) created specifically for this purpose. We control and, therefore, consolidate the SPE in our consolidated financial statements. The SPE transfers ownership and control of qualifying accounts receivable to PNC up to the maximum purchase commitment. We and our related subsidiaries have no continuing involvement in the transferred accounts receivable, other than collection and administrative responsibilities, and, once sold, the accounts receivable are no longer available to satisfy our creditors or our related subsidiaries. We account for accounts receivable sold to the banking counterparty as a sale of financial assets and derecognize the trade accounts receivable from our Consolidated Balance Sheets.

The total outstanding balance of trade accounts receivable that have been sold and derecognized is $65.0 million as of September 30, 2023. The SPE owned $145.7 million of trade accounts receivable as of September 30, 2023, which are included in Accounts receivable, net on the Consolidated Balance Sheets. For the three and nine months ended September 30, 2023, we received $40.0 million and $65.0 million, respectively, in cash proceeds from the Facility, which are included in cash from operating activities in the Consolidated Statements of Cash Flows. As of September 30, 2023, we had $35.0 million available capacity under the Facility.

Customer concentration

Customer concentration — We operate in multiple industry sectors encompassing the construction of commercial, industrial and public works infrastructure assets primarily throughout the United States. Typically, the top ten customers in any one calendar year generate revenue that is approximately 40% to 50% of total revenue; however, the companies that comprise the top ten customers vary from year to year.

For the three and nine months ended September 30, 2023, approximately 44.1% and 38.2%, respectively, of total revenue was generated from our top ten customers and no one customer accounted for more than 10% of our total revenue.

For the three and nine months ended September 30, 2022, approximately 53.3% and 48.4%, respectively, of total revenue was generated from our top ten customers. For the three months ended September 30, 2022, one renewable energy customer represented approximately 11.3% of total revenue and for the nine months ended September 30, 2022, no one customer accounted for more than 10% of our total revenue.