Defined Benefit Pension Plans Schedule of Amounts Recognized in the Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014
Schedule of Amounts Recognized in the Consolidated Balance Sheets [Line Items]
Plan Assets in Other Long Term Assets	$ (359)				$ (567)
Current Portion of Pension Plan Liability in Wages and Benefits Payable	3,493				4,122
Long-term portion of pension plan liability	85,971	$ 94,100	$ 93,918	$ 91,652	101,862	$ 82,529	$ 87,988	$ 89,498
Net Pension Plan Benefit Liability	$ (89,105)				$ (105,417)