Income Taxes Deferred Tax Summary (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Abstract]
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	$ 4,535	$ 1,737
Deferred Tax Liabilities, Noncurrent	(71,041)	(65,488)
Deferred Tax Liabilities, Net	$ (66,506)	$ (63,751)