Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Net Sales		$ 344,441	$ 442,395	$ 1,123,496	$ 1,352,839
Cost of sales		266,687	316,241	865,558	991,876
Gross profit		77,754	126,154	257,938	360,963
Selling, general and administrative expenses		41,885	42,187	125,910	123,341
Legal and environmental charges		0	(5,589)	0	(5,589)
Profit from operations		35,869	89,556	132,028	243,211
Other income (loss):
Interest income		3,577	4,621	12,631	12,159
Other, net		7,974	(3,616)	7,042	(5,107)
Income before income taxes		47,420	90,561	151,701	250,263
Provision (benefit) for income taxes		(472)	16,264	15,676	47,934
Net income		$ 47,892	$ 74,297	$ 136,025	$ 202,329
Income per share:
Basic (in dollars per share)		$ 0.28	$ 0.44	$ 0.80	$ 1.20
Diluted (in dollars per share)		0.28	0.44	0.80	1.20
Dividends declared (per share) (in dollars per share)		$ 0.115	$ 0.115	$ 0.345	$ 0.345
Weighted average common shares outstanding:
Basic (in shares)		169,125	168,795	169,079	168,679
Diluted (in shares)	[1]	169,467	169,314	169,371	169,247

[1] Common stock equivalents not included in the computation of diluted earnings per share because the impact would have been anti-dilutive were 0 shares for the three month periods ended December 31, 2018 and 2019, and 8 shares and 2 shares for the nine months ended December 31, 2018 and 2019, respectively.