Income taxes (Additional information) (Details) - USD ($) $ in Thousands	Mar. 21, 2017	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Line Items]
Operating loss carryforwards not subject to expiration		$ 2,383	$ 2,870
CODI	$ 60,398
Federal
Income Tax Disclosure [Line Items]
Operating loss carryforwards		1,152,714
Operating loss carryforwards subject to expiration		1,011,368	1,011,368
Operating loss carryforwards not subject to expiration		141,346
Percentage depletion carryforwards, not subject to expiration		11,347
Operating loss carryforwards, subject to limitation			760,067
Operating loss carryforwards, not subject to limitation		141,346	$ 251,301
State
Income Tax Disclosure [Line Items]
Operating loss carryforwards		1,404,542
Operating loss carryforwards subject to expiration		$ 1,421,847