Employee Benefits (Net Periodic Benefit Cost) (Details) (Other Postretirement Benefit Plans, Defined Benefit, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Other Postretirement Benefit Plans, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 3,843	$ 4,378	$ 2,988
Interest cost	5,156	5,651	5,379
Expected return on plan assets	(1,951)	(1,714)	(1,823)
Prior service benefit	5,657	5,877	5,927
Net (gain) loss	(626)	615	(39)
Net periodic benefit cost	$ 765	$ 3,053	$ 578