Accounting Policies Accounting Policies (Details) - USD ($) $ in Thousands	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to retained earnings		$ 0
Accumulated Other Comprehensive Income (Loss)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to retained earnings	$ (650)	(650)
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to retained earnings	$ 650	$ 650