Employee Benefits - Plan Obligation, Funded Status and Amounts Recognized in Financial Statements and Underlying Actuarial and Other Assumptions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Change in benefit obligation:
Plan amendments	$ 0	$ 0
Change in plan assets:
Fair value at beginning of period	216,614
Fair value at end of period	240,463	216,614
Post-Retirement Benefits Other Than Pensions
Change in benefit obligation:
Benefit obligation at beginning of period	26,169	23,979
Service cost	338	291	$ 290
Interest cost	648	789	941
Benefits and expenses paid (premiums)	(1,230)	(921)
Actuarial (gain) loss	(658)	2,031
Benefit obligation at end of period	25,267	26,169	23,979
Change in plan assets:
Fair value at beginning of period	0	0
Employer contributions	1,230	921
Benefits paid	(1,230)	(921)
Fair value at end of period	0	0	$ 0
Funded status at end of period	(25,267)	(26,169)
Amounts recognized in the balance sheet:
Current liabilities	(1,537)	(1,443)
Noncurrent liabilities	(23,730)	(24,726)
Defined benefit pension plan liabilities	(25,267)	(26,169)
Amounts recognized in accumulated other comprehensive loss:
Prior service costs	(5,760)	(7,507)
Net actuarial loss	9,344	10,977
Amounts recognized in accumulated other comprehensive loss	3,584	3,470
Ripplewood Transaction Shell Chemicals | Post-Retirement Benefits Other Than Pensions
Amounts recognized in accumulated other comprehensive loss:
Retirement plan asset—noncurrent	$ 3,000	$ 4,400