Other Employee Benefit Plans Other Employee Benefit Plans (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Change in benefit obligation:
Benefit obligation at January 1	$ 11,813	$ 12,551
Service costs	156	166	$ 254
Interest costs	353	444	883
Actuarial loss (gain)	(199)	890
Benefits paid	(312)	(1,338)
Foreign currency exchange changes	(385)	(900)
Benefit obligation at December 31	11,426	11,813	$ 12,551
Fair value of plan assets at December 31	0	0
Unfunded status at December 31	11,426	11,813
Amounts recognized in the Consolidated Balance Sheets:
Current liabilities	307	335
Non-current liabilities	$ 11,119	$ 11,478
Supplemental Executive Retirement Plan (SERP)
Net periodic benefit cost:
Discount rate	3.75%	4.75%
Rate of increase in compensation levels	3.00%	3.00%
Funded status and projected benefit obligation:
Discount rate	4.00%	3.75%
Rate of increase in compensation levels	3.00%	3.00%
Defined benefit pension plan for employees outside the United States
Net periodic benefit cost:
Discount rate	2.60%	1.90%
Funded status and projected benefit obligation:
Discount rate	2.60%	1.90%