Employee Benefit Plans (Schedule of Changes in Accumulated Postretirement Benefits Obligations) (Details) - Postretirement Medical and Life Benefit Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Obligation at the Beginning of Year	$ 746	$ 671
Unrecognized Loss (Gain)	22	46
Components of Net Periodic Postretirement Benefit Cost
Service Cost	42	41	$ 40
Interest Cost	26	28	23
Net Expected Benefit Payments	(53)	(40)
Obligation at End of Year	$ 783	$ 746	$ 671