Income Taxes - Components of Provisional Tax Expense Related to Tax Law Changes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Deferred taxes related to items recognized in continuing operations	$ 0	$ 0	$ (1,895)
Deferred taxes on net actuarial loss on defined benefit post-retirement benefit plans	0	0	0
Deferred taxes on net unrealized losses on available for sale investment securities	0	0	0
Provisional Tax Expense Related to Tax Law Changes	$ 0	$ 0	$ (1,895)