Industry Segment and Foreign Operations - Sales Revenue by Product Groups (Details) - USD ($)	3 Months Ended		9 Months Ended	12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenue				$ 1,970,129,000	$ 1,563,150,000	$ 1,804,436,000
Cost of goods sold				1,381,373,000	1,165,279,000	1,390,007,000
Gross profit				588,756,000	397,871,000	414,429,000
Operating expenses
Research and development				40,406,000	40,743,000	41,073,000
Selling, general, and administrative				164,167,000	161,944,000	149,800,000
Depreciation and amortization				126,475,000	126,022,000	136,171,000
Gain on insurance proceeds				0	0	(32,850,000)
Loss on disposal of fixed assets				879,000	750,000	773,000
Operating income (loss)				256,829,000	(331,588,000)	119,462,000
Other income (expense)				(209,000)	995,000	3,339,000
Gain (loss) on disposition and exit of business activities				(149,000)	175,189,000	0
Loss on extinguishment of debt				0	(40,843,000)	(3,521,000)
Earnings of unconsolidated joint venture				461,000	457,000	506,000
Interest expense, net				(41,840,000)	(57,930,000)	(75,782,000)
Income (loss) before income taxes				215,092,000	(253,720,000)	44,004,000
Goodwill, impairment loss				0	400,000,000	0
Polymer
Segment Reporting Information [Line Items]
Revenue				1,098,785,000	857,558,000	1,052,968,000
Cost of goods sold				775,804,000	627,297,000	820,410,000
Gross profit				322,981,000	230,261,000	232,558,000
Operating expenses
Research and development				29,869,000	29,972,000	29,392,000
Selling, general, and administrative				91,360,000	90,074,000	86,025,000
Depreciation and amortization				51,042,000	52,910,000	59,151,000
Gain on insurance proceeds						0
Loss on disposal of fixed assets				292,000	503,000	(647,000)
Operating income (loss)				150,418,000	56,802,000	57,343,000
Goodwill, impairment loss				0	0
Chemical
Segment Reporting Information [Line Items]
Revenue				871,344,000	705,592,000	751,468,000
Cost of goods sold				605,569,000	537,982,000	569,597,000
Gross profit				265,775,000	167,610,000	181,871,000
Operating expenses
Research and development				10,537,000	10,771,000	11,681,000
Selling, general, and administrative				72,807,000	71,870,000	63,775,000
Depreciation and amortization				75,433,000	73,112,000	77,020,000
Gain on insurance proceeds						(32,850,000)
Loss on disposal of fixed assets				587,000	247,000	(126,000)
Operating income (loss)				106,411,000	(388,390,000)	$ 62,119,000
Goodwill, impairment loss	$ 0	$ 400,000,000	$ 400,000,000	$ 0	$ 400,000,000