Income Taxes - Allocation of Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Income tax expense (benefit)	$ 9,447	$ (736)	$ (17,881)
Income tax recorded in accumulated other comprehensive loss	116	685	(2,488)
Total income tax expense (benefit)	$ 9,563	$ (51)	$ (20,369)