Supplemental Balance Sheet, Income Statement and Cash Flow Information - Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued liabilities
Accrued compensation	$ 97,003	$ 92,358
Deferred revenue and proceeds on insurance and asset sales	89,051	149,266
Other taxes payable	31,472	33,199
Workers' compensation liabilities	30,214	16,316
Interest payable	51,316	59,718
Litigation reserves	14,736	24,926
Current liability to discontinued operations		2,445
Dividends declared and payable	7,832	25,330
Other accrued liabilities	11,658	14,354
Accrued liabilities	$ 333,282	$ 417,912