Investments and other assets - Components of Investments and Other Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Investments, All Other Investments [Abstract]
Cash value life insurance	$ 53,058	$ 52,883
Equity method investments	27,947	32,067
Other equity investments	16,939	20,271
Deferred debt issuance costs	7,607	9,378
Other long-term assets	26,166	21,620
Total	$ 131,717	$ 136,219