Additional Balance Sheet Detail and Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands		Mar. 31, 2020	Dec. 31, 2019
Other Liabilities Disclosure [Abstract]
Other Accrued Liabilities		$ 3,395	$ 4,163
Accrued Income Taxes, Current		1,908	11,243
Accrual for Taxes Other than Income Taxes, Current		2,692	3,554
Interest Payable, Current		5,266	1,833
Operating Lease, Liability, Current		12,198	13,104
Accrued Salaries, Current		14,567	20,047
Silvertip acquisition contingent consideration		0	25,000
Deferred Revenue	[1]	9,909	16,672
Accrued liabilities and other		$ 49,935	$ 95,616

[1] ⁽¹⁾ See Note 17 -- Commitments and Contingencies for additional details on deferred revenue liabilities