Supplemental Balance Sheet and Income Statement Information - Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accrued liabilities
Accrued compensation	$ 77,344	$ 97,003
Deferred revenue and proceeds on insurance and asset sales	60,616	89,051
Other taxes payable	33,681	31,472
Workers' compensation liabilities	15,214	30,214
Interest payable	25,771	51,316
Litigation reserves	14,282	14,736
Dividends declared and payable	3,653	7,832
Other accrued liabilities	16,620	11,658
Accrued liabilities	$ 247,181	$ 333,282