Income Taxes - Principal Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred income tax liabilities:
Tax in excess of book depreciation	$ 27,459	$ 28,329
Intangible assets	23,695	26,474
Operating leases	11,149	12,697
Taxes on unremitted foreign earnings	6,601	0
Other deferred tax liabilities	533	2,178
Total deferred income tax liabilities	69,437	69,678
Deferred income tax assets:
Interest expense limitation	3,811	14,073
Goodwill	25,653	386
Inventories	3,224	2,447
Interest rate swap	3,611	2,838
Pension/Personnel accruals	2,909	1,669
Operating leases	13,209	14,438
Net operating loss carryforwards	18,659	15,486
R&D credit carryforwards	0	2,463
Non-U.S. credit carryforwards	3,574	3,419
Accruals and reserves	2,399	2,335
Other deferred tax assets	2,891	1,157
Deferred income tax assets before valuation allowance	79,940	60,711
Valuation allowance on deferred tax assets	(21,681)	(15,494)
Total deferred income tax assets	58,259	45,217
Net deferred income tax liabilities	$ 11,178	$ 24,461