Employee Benefit Plans - Components of Net Periodic Benefit Cost and Other Amounts Recognized in Other Comprehensive Income ( (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($)
Pension Plan [Member]
Components of net periodic benefit (gain) cost
Service cost	$ 0
Interest cost	45
Expected return on plan assets	(73)
Amortization of prior service cost	0
Amortization of net obligation at transition	0
Recognized net loss due to settlement	0
Recognized net actuarial loss	0
Net periodic benefit (gain) cost	(28)
Other changes in plan assets and benefit obligations recognized in accumulated other comprehensive (income) loss
Net loss (gain)	11
Amortization of prior service cost	0
Net obligation at transition	0
Total recognized in other comprehensive loss (income)	11
Total recognized in net periodic benefit cost and other comprehensive loss (income)	(17)
PRB Plan [Member]
Components of net periodic benefit (gain) cost
Service cost	0
Interest cost	2
Expected return on plan assets
Amortization of prior service cost	0
Amortization of net obligation at transition	0
Recognized net loss due to settlement	0
Recognized net actuarial loss	0
Net periodic benefit (gain) cost	2
Other changes in plan assets and benefit obligations recognized in accumulated other comprehensive (income) loss
Net loss (gain)	(9)
Amortization of prior service cost	0
Net obligation at transition	0
Total recognized in other comprehensive loss (income)	(9)
Total recognized in net periodic benefit cost and other comprehensive loss (income)	$ (7)