Segment and Geographic Information - Schedule of Net Sales to External Customers and Location of Net Plant, Equipment and Timberlands (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 235,282	$ 233,473	$ 216,183	$ 231,560	$ 230,972	$ 232,515	$ 235,053	$ 229,133	$ 916,498	$ 927,673	$ 866,286
Plant, Equipment and Timberlands – Net	543,267				537,421				543,267	537,421	556,044
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									166,131	167,887	124,690
Plant, Equipment and Timberlands – Net	103,570				105,763				103,570	105,763	109,797
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									489,655	504,012	483,628
Plant, Equipment and Timberlands – Net	286,591				274,146				286,591	274,146	286,839
United Kingdom [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									73,604	70,018	76,053
Plant, Equipment and Timberlands – Net	50,140				52,039				50,140	52,039	50,483
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									112,128	121,789	114,877
Plant, Equipment and Timberlands – Net	68,975				72,436				68,975	72,436	74,448
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									74,980	63,967	67,038
Plant, Equipment and Timberlands – Net	$ 33,991				$ 33,037				$ 33,991	$ 33,037	$ 34,477