Defined Benefit Pension Plans Schedule of Amounts Recognized in Other Comprehensive Income (loss), pre-tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Net actuarial (gain) loss	$ (3,209)	$ 6,316	$ (6,894)
Settlement/ curtailment loss	2	(1,343)	(336)
OCI, Defined Benefit Plan, Curtailment	586	0	0
Plan asset (gain) loss	(192)	(64)	343
Amortization of net actuarial gain (loss)	(2,308)	(1,351)	(1,979)
Amortization of prior service cost	(62)	(58)	(59)
Other	0	4	(46)
Other comprehensive (income) loss	$ (5,183)	$ 3,504	$ (8,971)