Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 8,221	$ 121,701
Accounts receivable, net	309,527	106,748
Inventories	75,012	68,238
Prepaid expenses and other assets	17,322	25,310
Total current assets	410,082	321,997
Property, plant and equipment, net	378,167	336,537
Goodwill and other intangible assets, net	73,560	73,665
Operating lease assets	33,672	34,382
Other assets	4,809	3,911
Total assets	900,290	770,492
Current liabilities:
Accounts payable	39,167	38,622
Accrued expenses and other liabilities	55,058	62,331
Accrued warranty	5,400	5,400
Line of credit	136,000
Total current liabilities	235,625	106,353
Operating lease liabilities	27,420	28,579
Non-current accrued warranty	24,145	24,073
Deferred income taxes	22,956	22,956
Total liabilities	310,146	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; 140,643,173 and140,577,005 shares issued and 115,361,396 and 115,799,503 shares outstanding at March 31, 2021 and December 31, 2020, respectively	1,406	1,406
Additional paid-in capital	124,678	126,087
Retained earnings	785,856	737,311
Treasury stock, at cost, 25,281,777 and 24,777,502 shares at March 31, 2021 and December 31, 2020, respectively	(321,796)	(276,273)
Total stockholders' equity	590,144	588,531
Total liabilities and stockholders' equity	$ 900,290	$ 770,492