Basis of Presentation (Policies)

6 Months Ended

Jun. 30, 2022

Basis of Presentation

Reclassification

Reclassification — Certain previously reported amounts have been reclassified to conform to the current period presentation.

Restricted cash

Restricted cash — Restricted cash consists primarily of 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. 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):

	June 30,
	2022		2021
Cash and cash equivalents	$	91,254	$	177,979
Restricted cash included in prepaid expense and other current assets		5,056		4,801
Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	$	96,310	$	182,780

	December 31,
	2021		2020
Cash and cash equivalents	$	200,512	$	326,744
Restricted cash included in prepaid expense and other current assets		5,131		4,231
Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	$	205,643	$	330,975

Depreciation

Depreciation — Effective January 1, 2022, we changed our estimates of the useful lives of certain equipment to better reflect the estimated periods during which these assets will remain in service. The estimated useful lives of equipment that previously ranged three to seven years were increased to a range of three to ten years. The effect of this change in estimate reduced depreciation expense by $5.3 million, increased net income by $4.2 million, and increased basic and diluted earnings per share by $0.08 for the three months ended June 30, 2022. The effect of this change in estimate reduced depreciation expense by $11.1 million, increased net income by $8.8 million, and increased basic and diluted earnings per share by $0.16 for the six months ended June 30, 2022.

Customer concentration

Customer concentration — We operate in multiple industry segments 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 vary from year to year.

For the three and six months ended June 30, 2022, approximately 50.8% and 47.4%, respectively, of total revenue was generated from our top ten customers and no one customer accounted for more than ten percent of our total revenue.

For the three and six months ended June 30, 2021, approximately 42.3% and 43.6%, respectively, of total revenue was generated from our top ten customers and no one customer accounted for more than ten percent of our total revenue.