Income Taxes - Allocation of Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Income tax expense (benefit)	$ 13,670	$ 9,447	$ (736)
Income tax recorded in accumulated other comprehensive loss, Income tax (benefit) expense	(386)	116	685
Total income tax expense (benefit)	$ 13,284	$ 9,563	$ (51)