Segment Information - Geographic Distribution and Net Sales by Product (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net sales and long-lived assets by geographical area
Net Sales	$ 241,845	$ 284,178	$ 308,007	$ 244,779	$ 231,681	$ 262,476	$ 263,002	$ 219,867	$ 1,078,809	$ 977,025	$ 860,661
Long-Lived Assets	264,346				282,059				264,346	282,059	240,670
Wood construction products
Net sales and long-lived assets by geographical area
Net Sales									913,202	833,200	732,414
Concrete construction products
Net sales and long-lived assets by geographical area
Net Sales									165,317	143,102	128,247
Other
Net sales and long-lived assets by geographical area
Net Sales									290	723	0
United States
Net sales and long-lived assets by geographical area
Net Sales									860,482	758,181	702,071
Long-Lived Assets	210,063				223,184				210,063	223,184	192,787
Canada
Net sales and long-lived assets by geographical area
Net Sales									46,874	43,176	38,269
Long-Lived Assets	4,257				4,650				4,257	4,650	4,473
United Kingdom
Net sales and long-lived assets by geographical area
Net Sales									27,194	23,157	20,751
Long-Lived Assets	1,417				1,459				1,417	1,459	1,183
Germany
Net sales and long-lived assets by geographical area
Net Sales									22,950	21,821	33,062
Long-Lived Assets	13,221				14,153				13,221	14,153	12,582
France
Net sales and long-lived assets by geographical area
Net Sales									40,182	36,677	20,905
Long-Lived Assets	7,891				9,152				7,891	9,152	8,349
Poland
Net sales and long-lived assets by geographical area
Net Sales									10,200	20,409	6,633
Long-Lived Assets	2,794				2,471				2,794	2,471	1,830
Sweden
Net sales and long-lived assets by geographical area
Net Sales									15,461	16,421	0
Long-Lived Assets	1,154				1,068				1,154	1,068	0
Denmark
Net sales and long-lived assets by geographical area
Net Sales									11,682	14,723	15,728
Long-Lived Assets	1,454				1,601				1,454	1,601	1,249
Norway
Net sales and long-lived assets by geographical area
Net Sales									12,324	12,902	0
Long-Lived Assets	0				229				0	229	0
Switzerland
Net sales and long-lived assets by geographical area
Net Sales									6,939	5,593	6,549
Long-Lived Assets	8,067				8,748				8,067	8,748	8,469
Australia
Net sales and long-lived assets by geographical area
Net Sales									6,119	5,501	4,741
Long-Lived Assets	199				268				199	268	239
Belgium
Net sales and long-lived assets by geographical area
Net Sales									5,547	5,050	1,286
Long-Lived Assets	1,961				2,065				1,961	2,065	1,798
The Netherlands
Net sales and long-lived assets by geographical area
Net Sales									5,068	4,834	4,909
Long-Lived Assets	81				110				81	110	21
New Zealand
Net sales and long-lived assets by geographical area
Net Sales									3,061	2,604	2,474
Long-Lived Assets	111				130				111	130	163
Chile
Net sales and long-lived assets by geographical area
Net Sales									3,233	2,314	1,572
Long-Lived Assets	41				61				41	61	56
Other countries
Net sales and long-lived assets by geographical area
Net Sales									1,493	3,662	1,711
Long-Lived Assets	$ 11,635				$ 12,710				$ 11,635	$ 12,710	$ 7,471