Defined Benefit Pension Plans Components of Pension Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service costs--increase in benefit obligation earned	$ 370	$ 35	$ 51
Interest cost on projected benefit obligation	1,243	1,486	1,618
Expected return on plan assets	(1,044)	(1,576)	(1,993)
Curtailment loss	0	49	0
Settlement loss	2,346	2,915	2,065
Amortization of net actuarial loss	951	1,400	708
Amortization of prior service cost	0	6	14
Net pension expense of defined benefit pension plans	$ 3,866	$ 4,315	$ 2,463