Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 62,650	$ 72,011
Accounts receivable, net	170,424	163,135
Inventories, net	175,049	170,376
Prepaid expenses and other current assets	17,164	18,071
Total current assets	425,287	423,593
Property, plant, and equipment, net	355,405	383,562
Operating lease assets, net	29,093	33,140
Goodwill, net	76,579	76,489
Other intangible assets, net	195,612	205,749
Other noncurrent assets	33,748	29,727
Total assets	1,115,724	1,152,260
Current liabilities:
Current portion of long-term debt	18,231	17,778
Accounts payable	55,574	46,433
Accrued liabilities	45,388	44,504
Current operating lease liabilities	7,169	7,620
Income taxes payable	2,769	2,413
Deferred revenue	45,210	43,384
Total current liabilities	174,341	162,132
Long-term debt	160,354	165,759
Long-term operating lease liabilities	28,186	29,166
Deferred income taxes	4,860	14,263
Other noncurrent liabilities	26,049	23,309
Total liabilities	393,790	394,629
Stockholders' equity:
Common stock, $.01 par value, 200,000,000 shares authorized, 73,908,412 shares and 73,288,976 shares issued, respectively	739	733
Additional paid-in capital	1,101,959	1,122,945
Retained earnings	314,479	329,327
Accumulated other comprehensive loss	(69,754)	(71,385)
Treasury stock, at cost, 12,508,964 and 12,283,817 shares, respectively	(625,489)	(623,989)
Total stockholders' equity	721,934	757,631
Total liabilities and stockholders' equity	$ 1,115,724	$ 1,152,260