Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current Assets:
Cash and cash equivalents	$ 141,053	$ 121,701
Accounts receivable, net	151,096	106,748
Inventories	83,753	68,238
Prepaid expenses and other assets	25,152	25,310
Total current assets	401,054	321,997
Property, plant and equipment, net	460,365	336,537
Goodwill and other intangible assets, net	19,001	73,665
Operating lease assets	34,571	34,382
Other assets	5,330	3,911
Total Assets	920,321	770,492
Current Liabilities:
Accounts payable	24,861	38,622
Accrued expenses and other liabilities	58,041	62,331
Accrued warranty	5,800	5,400
Total current liabilities	88,702	106,353
Operating lease liabilities	28,263	28,579
Non-current accrued warranty	22,795	24,073
Deferred income taxes	43,967	22,956
Other long-term liabilities	11,560	0
Total Liabilities	195,287	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; 140,734,753 and 140,577,005 shares issued and 115,148,152 and 115,799,503 shares outstanding at December 31, 2021 and 2020, respectively	1,407	1,406
Additional paid-in capital	127,787	126,087
Retained earnings	946,048	737,311
Treasury stock, at cost, 25,586,601 and 24,777,502 shares at December 31, 2021 and 2020, respectively	(350,208)	(276,273)
Total Stockholders' Equity	725,034	588,531
Total Liabilities and Stockholders' Equity	$ 920,321	$ 770,492