Income Taxes Impact of New Tax Legislation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
AMT Receivable Resulting from TCJA	$ 37,019
Change in Impact of AMT Repeal on Current Taxes	$ 1,902
AMT Installment Payment End Date	Dec. 31, 2021
Impact of AMT Repeal on Current Taxes		$ 29,581
AMT Related to Filing of 2017 Tax Return		$ 5,536