Employee Benefit Plans (Schedule of Changes in Fair Value of Plan Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	$ 68,435
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	84,770	$ 68,435
Defined Benefit Plan, Funded Status of Plan	(77,185)	(73,804)
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	68,435	66,757
Defined Benefit Plan, Actual Return on Plan Assets	6,584	(2,795)
Defined Benefit Plan, Contributions by Employer	15,950	8,953
Defined Benefit Plan, Contributions by Plan Participants	0	0
Defined Benefit Plan, Settlements, Plan Assets	(3,152)	0
Defined Benefit Plan, Benefits Paid	(3,047)	(4,480)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	84,770	68,435
Defined Benefit Plan, Funded Status of Plan	(77,185)	(73,804)
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	410	380
Defined Benefit Plan, Contributions by Plan Participants	305	229
Defined Benefit Plan, Settlements, Plan Assets	0	0
Defined Benefit Plan, Benefits Paid	(715)	(609)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	0	0
Defined Benefit Plan, Funded Status of Plan	$ (60,524)	$ (63,307)