Supplemental Balance Sheet and Income Statement Information - Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accrued liabilities
Accrued compensation	$ 79,085	$ 92,358
Deferred revenue and proceeds on insurance and asset sales	100,030	149,266
Other taxes payable	24,650	33,199
Workers' compensation liabilities	15,214	16,316
Interest payable	18,570	59,718
Litigation reserves	15,547	24,926
Current liability to discontinued operations		2,445
Dividends declared and payable	7,830	25,330
Other accrued liabilities	18,255	14,354
Accrued liabilities	$ 279,181	$ 417,912