Employee Benefit Plans (Schedule of Net Funded Status) (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		$ 84,770	$ 68,435
Defined Benefit Plan, Benefit Obligation		161,955	142,239
Defined Benefit Plan, Funded Status of Plan, Total		(77,185)	(73,804)
Qualified Pension Plans Defined Benefit [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets		84,770	68,435
Defined Benefit Plan, Benefit Obligation		96,418	83,870
Defined Benefit Plan, Funded Status of Plan, Total		(11,648)	(15,435)
Non Qualified Pension Plans Defined Benefit [Member]
Defined Benefit Plan Change In Benefit Obligation [Line Items]
Defined Benefit Plan, Fair Value of Plan Assets	[1]	0	0
Defined Benefit Plan, Benefit Obligation	[1]	65,537	58,369
Defined Benefit Plan, Funded Status of Plan, Total	[1]	$ (65,537)	$ (58,369)

[1] For non-qualified plans, there are no required funding levels.