Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 20,731	$ 32,054
Accounts receivable, net of allowance of $3,319 and $3,529	199,598	197,990
Inventories, net	107,004	98,307
Prepaid expenses and other current assets	24,684	19,671
Assets of discontinued operations	0	77,438
Total current assets	352,017	425,460
Property, plant, and equipment, net	91,717	89,562
Operating lease assets	23,465	25,229
Goodwill	523,446	514,279
Acquired intangibles	151,877	156,365
Other assets	12,669	1,599
Total assets	1,155,191	1,212,494
Current liabilities:
Accounts payable	135,130	134,738
Accrued expenses	71,946	83,505
Billings in excess of cost	51,591	34,702
Liabilities of discontinued operations	0	49,295
Total current liabilities	258,667	302,240
Long-term debt	58,023	85,636
Deferred income taxes	37,996	39,057
Non-current operating lease liabilities	16,165	17,730
Other non-current liabilities	25,932	24,026
Stockholders’ equity:
Preferred stock, $0.01 par value; authorized 10,000 shares; none outstanding	0	0
Common stock, $0.01 par value; authorized 50,000 shares; 33,711 shares and 33,568 shares issued and outstanding in 2021 and 2020	337	336
Additional paid-in capital	308,147	304,870
Retained earnings	482,705	469,943
Accumulated other comprehensive income (loss)	764	(2,461)
Cost of 1,082 and 1,028 common shares held in treasury in 2021 and 2020	(33,545)	(28,883)
Total stockholders’ equity	758,408	743,805
Total liabilities and shareholders' equity	$ 1,155,191	$ 1,212,494