Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 123,654	$ 139,330
Marketable securities, at fair value	125,773	125,012
Accounts and notes receivable, less allowance for doubtful accounts of $53,819 and $59,906 as of March 31, 2021 and December 31, 2020, respectively	252,778	255,474
Inventories and supplies	29,170	31,586
Prepaid expenses and other assets	40,815	21,001
Total current assets	572,190	572,403
Property and equipment, net	27,722	26,561
Goodwill	51,084	51,084
Other intangible assets, less accumulated amortization of $24,507 and $23,466 as of March 31, 2021 and December 31, 2020, respectively	17,146	18,187
Notes receivable — long–term portion, less allowance for doubtful accounts of $7,283 and $7,895 as of March 31, 2021 and December 31, 2020, respectively	31,795	34,417
Deferred compensation funding, at fair value	46,981	46,825
Deferred income taxes	35,891	35,554
Total assets	782,809	785,031
Current liabilities:
Accounts payable	47,754	52,239
Accrued payroll and related taxes	37,691	70,614
Other accrued expenses	30,852	17,797
Income taxes payable	7,908	0
Accrued insurance claims	22,702	21,610
Total current liabilities	146,907	162,260
Accrued insurance claims — long-term portion	60,348	60,818
Deferred compensation liability	46,876	46,827
Accrued payroll and related taxes - noncurrent	23,302	23,302
Lease liability — long-term portion	12,274	11,363
Commitments and contingencies (Note 15)
STOCKHOLDERS’ EQUITY:
Common stock, $0.01 par value; 100,000 shares authorized; 75,958 and 75,798 shares issued, and 74,721 and 74,485 shares outstanding as of March 31, 2021 and December 31, 2020, respectively	760	758
Additional paid-in capital	286,522	282,206
Retained earnings	210,020	200,893
Accumulated other comprehensive income, net of taxes	4,292	5,563
Common stock in treasury, at cost, 1,237 and 1,313 shares as of March 31, 2021 and December 31, 2020, respectively	(8,492)	(8,959)
Total stockholders’ equity	493,102	480,461
Total liabilities and stockholders’ equity	$ 782,809	$ 785,031