Income Taxes - Reconciliation of our uncertain tax positions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in unrecognized tax benefits
Balance as of January 1	$ 25,711	$ 33,203	$ 179,255
Additions for tax positions of prior years	1,003	308	25,119
Reductions for tax positions of prior years	(860)	(7,800)	(171,171)
Settlements	(84)
Balance as of December 31	25,770	25,711	33,203
Interest and penalties on unrecognized tax benefits	7,700	6,700	9,700
Liability related to unrecognized tax benefit for accrued interest and penalties	$ 800	$ 1,000	$ 500