Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 64,892	$ 85,845	$ 69,117
Gross increases – tax positions of prior periods	74	2,704	2,692
Gross increases – current period tax positions	2,006	3,021	27,163
Gross decreases – tax positions of prior periods	(5,201)	(15,287)	(277)
Gross decreases – lapse of applicable statute of limitations	(28,672)	(6,186)	(12,850)
Gross decreases – settlements	(5,740)	(5,205)	0
Balance at end of year	$ 27,359	$ 64,892	$ 85,845