Investments and other assets - Components of Investments and Other Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Investments, All Other Investments [Abstract]
Cash value life insurance	$ 50,730	$ 52,462
Equity method investments	36,646	27,650
Other equity investments	32,420	32,383
Deferred debt issuance costs	10,178	10,921
Other long-term assets	21,109	21,853
Total	$ 151,083	$ 145,269