Segment Information (Details 2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Net sales and long-lived assets by geographical area
Cash and cash equivalents	$ 137,413	$ 167,059	$ 168,514	$ 226,537
Net sales	244,779	219,867
Wood construction products
Net sales and long-lived assets by geographical area
Net sales	212,547	190,877
Concrete construction products
Net sales and long-lived assets by geographical area
Net sales	32,156	28,817
Other
Net sales and long-lived assets by geographical area
Net sales	76	173
Corporate, Non-Segment [Member]
Net sales and long-lived assets by geographical area
Cash and cash equivalents	$ 53,400	$ 92,100	$ 80,200