Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Revenues		$ 181,716	$ 199,897
Costs and expenses:
Cost of goods sold		154,215	139,155
Selling, general and administrative expenses		16,570	13,656
Gain on sale of facility		(9,176)
Deltic merger-related costs	[1]		19,255
Total costs and expenses		161,609	172,066
Operating income		20,107	27,831
Interest expense, net	[2]	(5,464)	(5,660)
Loss on extinguishment of debt		(5,512)
Non-operating pension and other postretirement employee benefit costs		(980)	(1,857)
Income before income taxes		8,151	20,314
Income taxes		(1,591)	(5,717)
Net income		$ 6,560	$ 14,597
Net income per share:
Basic (in dollars per share)		$ 0.10	$ 0.29
Diluted (in dollars per share)		0.10	0.29
Dividends per share (in dollars per share)		$ 0.40	$ 0.40
Weighted-average shares outstanding:
Basic (in shares)		67,860	50,425
Diluted (in shares)		67,916	50,786

[1] For integration and restructuring costs related to the merger with Deltic see Note 3: Merger with Deltic.

[2] Bond discounts and deferred loan fees are reported within interest expense, net on the Condensed Consolidated Statement of Income.