Employee Benefit Plans, Financial Instruments Recorded At Fair Value On A Recurring Basis By The Plan (Details) - Pension Benefits [Member] - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	$ 109,746	$ 124,226	$ 116,216
Recurring Basis [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	109,746	124,226
Recurring Basis [Member] | Level 1 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	67,080	74,939
Recurring Basis [Member] | Level 2 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	42,666	49,287
Recurring Basis [Member] | Cash and Cash Equivalents [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	4,095	3,684
Recurring Basis [Member] | Cash and Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	4,095	3,684
Recurring Basis [Member] | Cash and Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	0	0
Recurring Basis [Member] | Foreign Equity Mutual Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	38,861	44,508
Recurring Basis [Member] | Foreign Equity Mutual Funds [Member] | Level 1 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	38,861	44,508
Recurring Basis [Member] | Foreign Equity Mutual Funds [Member] | Level 2 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	0	0
Recurring Basis [Member] | Equity Mutual Funds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	24,124	26,747
Recurring Basis [Member] | Equity Mutual Funds [Member] | Level 1 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	24,124	26,747
Recurring Basis [Member] | Equity Mutual Funds [Member] | Level 2 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	0	0
Recurring Basis [Member] | US Government Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	76	99
Recurring Basis [Member] | US Government Bonds [Member] | Level 1 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	0	0
Recurring Basis [Member] | US Government Bonds [Member] | Level 2 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	76	99
Recurring Basis [Member] | Corporate Bonds [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	42,590	49,188
Recurring Basis [Member] | Corporate Bonds [Member] | Level 1 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	0	0
Recurring Basis [Member] | Corporate Bonds [Member] | Level 2 [Member]
Defined Benefit Plan, Information about Plan Assets [Abstract]
Fair value of plan assets	$ 42,590	$ 49,188