Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 54,042	$ 121,701
Accounts receivable, net	265,560	106,748
Inventories	73,636	68,238
Prepaid expenses and other assets	19,782	25,310
Total current assets	413,020	321,997
Property, plant and equipment, net	424,974	336,537
Goodwill and other intangible assets, net	73,351	73,665
Operating lease assets	36,137	34,382
Other assets	5,969	3,911
Total assets	953,451	770,492
Current liabilities:
Accounts payable	45,415	38,622
Accrued expenses and other liabilities	105,193	62,331
Accrued warranty	5,400	5,400
Line of credit	0
Total current liabilities	156,008	106,353
Operating lease liabilities	29,716	28,579
Non-current accrued warranty	23,962	24,073
Deferred income taxes	22,956	22,956
Total liabilities	232,642	181,961
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.01 par value, 3,000,000 shares authorized; none issued and outstanding
Common stock, $0.01 par value, 180,000,000 shares authorized; 140,703,442 and 140,577,005 shares issued and 115,349,226 and 115,799,503 shares outstanding at September 30, 2021 and December 31, 2020, respectively	1,407	1,406
Additional paid-in capital	126,956	126,087
Retained earnings	921,016	737,311
Treasury stock, at cost, 25,354,216 and 24,777,502 shares at September 30, 2021 and December 31, 2020, respectively	(328,570)	(276,273)
Total stockholders' equity	720,809	588,531
Total liabilities and stockholders' equity	$ 953,451	$ 770,492