Income Tax Matters Income Tax Matters Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Operating Loss Carryforwards	$ 117,700,000	$ 117,700,000
Tax Credit Carryforward, Amount	11,400,000	11,400,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		(4,600,000)	$ (2,700,000)	$ (5,500,000)
Unrecognized Tax Benefits	1,500,000	1,500,000	1,500,000	1,800,000	$ 1,700,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	400,000	400,000
Accrued interest and penalties on unrecognized tax benefits	200,000	200,000	100,000
Accrued interest and penalties on unrecognized tax benefits, current	0	0
(Decrease) increase in interest and penalty	(100,000)	(100,000)		$ 0
Provisional decrease in deferred tax assets			$ 29,000,000.0
Provisional Transition Tax obligation	3,500,000
Accrued witholding taxes due to Canadian earnings deemed no longer permanently reinvested	1,600,000	1,600,000
Provisional Section 162(m) obligation	$ 2,300,000	$ 2,300,000