Employee Benefit Plans (Schedule of Changes in Fair Value of Plan Assets) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	$ 66,757	$ 59,559
Defined Benefit Plan, Funded Status of Plan	(71,439)	(51,636)
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	59,559	49,516
Defined Benefit Plan, Actual Return on Plan Assets	2,489	6,027
Defined Benefit Plan, Contributions by Employer	7,753	7,363
Defined Benefit Plan, Contributions by Plan Participants	0	0
Defined Benefit Plan, Benefits Paid	(3,044)	(3,347)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	66,757	59,559
Defined Benefit Plan, Funded Status of Plan	(71,439)	(51,636)
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	0	0
Defined Benefit Plan, Actual Return on Plan Assets	0	0
Defined Benefit Plan, Contributions by Employer	647	479
Defined Benefit Plan, Contributions by Plan Participants	174	128
Defined Benefit Plan, Benefits Paid	(821)	(607)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0	0
Defined Benefit Plan, Funded Status of Plan	$ (59,782)	$ (30,759)