Segment reporting (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) geographic_area	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of geographic areas | geographic_area			3
Net sales	$ 426,186	$ 410,219	$ 757,062	$ 702,077
Depreciation and amortization	22,406	24,390	44,907	48,782
Less: Interest expense	(19,702)	(25,783)	(40,447)	(50,448)
Income (loss) before income taxes	34,570	3,835	20,582	(28,501)
Capital expenditures	4,531	10,462	8,881	22,436
Total assets	1,771,497		1,771,497		$ 1,740,058
Earnings from equity method investee	3,126	3,402	5,925	4,969
Investment in equity method investee	51,459		51,459		50,034
Property, plant and equipment, net	446,974		446,974		475,575
United States
Segment Reporting Information [Line Items]
Net sales	407,764	391,721	723,144	668,458
Property, plant and equipment, net	408,159		408,159		422,486
Canada
Segment Reporting Information [Line Items]
Net sales	16,322	16,555	29,808	29,655
Property, plant and equipment, net	29,903		29,903		43,754
Mexico
Segment Reporting Information [Line Items]
Net sales	2,100	1,943	4,110	3,964
Property, plant and equipment, net	8,912		8,912		9,335
Drainage Pipe & Products
Segment Reporting Information [Line Items]
Earnings from equity method investee	3,100	3,400	5,900	5,000
Investment in equity method investee	51,459		51,459		50,034
Operating Segments | Drainage Pipe & Products
Segment Reporting Information [Line Items]
Net sales	235,596	241,680	405,830	405,414
Depreciation and amortization	8,300	9,456	16,545	18,658
Segment EBITDA and reconciliation to income (loss) before income taxes	57,414	48,997	83,466	74,063
Capital expenditures	2,366	7,519	5,396	15,448
Total assets	837,390		837,390		819,373
Operating Segments | Water Pipe & Products
Segment Reporting Information [Line Items]
Net sales	190,590	168,539	351,232	296,663
Depreciation and amortization	13,493	14,595	27,372	29,470
Segment EBITDA and reconciliation to income (loss) before income taxes	39,717	24,973	62,590	33,714
Capital expenditures	1,942	2,248	3,123	4,525
Total assets	865,237		865,237		862,542
Corporate and Other
Segment Reporting Information [Line Items]
Net sales	0	0	0	0
Depreciation and amortization	613	339	990	654
Segment EBITDA and reconciliation to income (loss) before income taxes	(20,453)	(19,962)	(40,120)	(37,048)
Capital expenditures	223	$ 695	362	$ 2,463
Total assets	$ 68,870		$ 68,870		$ 58,143