Pension Plans and Other Postretirement Benefits (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan [Member]
Change in benefit obligation:
Benefit obligations at beginning of year	$ 31,233	$ 34,279	$ 39,483
Service cost	650	450	360
Interest cost	1,244	1,189	1,679
Plan amendments	0	0	0
Actuarial loss (gain)	(220)	(1,371)	1,254
Benefits paid	(3,500)	(3,314)	(1,737)
Settlements	0	0	(6,760)
Benefit obligations at beginning of year	29,407	31,233	34,279
Change in plan assets:
Fair value of plan assets at beginning of year	27,667	31,408	35,879
Actual return on plan assets	1,766	200	2,535
Employer contributions	0	0	2,000
Benefits paid	(3,500)	(3,314)	(1,737)
Expenses paid	(487)	(627)	(509)
Settlements	0	0	(6,760)
Fair value of plan assets at end of year	25,446	27,667	31,408
Funded status	(3,961)	(3,566)	(2,871)
Prepaid (accrued) benefit expense	8,653	9,265	10,656
Total amount recognized in Consolidated Balance Sheets, all in Other liabilities	(3,961)	(3,566)	(2,871)
Amounts recognized in accumulated other comprehensive income (loss) ("AOCI"):
Prior service cost	0	0	0
Net actuarial loss	12,613	12,831	13,527
Total amount recognized in AOCI	12,613	12,831	13,527
Information for pension plans with an accumulated benefit obligation greater than plan assets:
Projected benefit obligation	29,407	31,233	34,279
Accumulated benefit obligation	29,407	31,233	34,279
Fair value of plan assets	25,446	27,667	31,408
Supplemental Defined Benefit Plans [Member]
Change in benefit obligation:
Benefit obligations at beginning of year	17,004	18,524	16,706
Service cost	0	0	0
Interest cost	687	654	716
Plan amendments	0	0	0
Actuarial loss (gain)	488	(845)	2,431
Benefits paid	(1,332)	(1,329)	(1,329)
Settlements	0	0	0
Benefit obligations at beginning of year	16,847	17,004	18,524
Change in plan assets:
Fair value of plan assets at beginning of year	0	0	0
Actual return on plan assets	0	0	0
Employer contributions	1,332	1,329	1,329
Benefits paid	(1,332)	(1,329)	(1,329)
Expenses paid	0	0	0
Settlements	0	0	0
Fair value of plan assets at end of year	0	0	0
Funded status	(16,847)	(17,004)	(18,524)
Prepaid (accrued) benefit expense	(11,210)	(11,622)	(12,024)
Total amount recognized in Consolidated Balance Sheets, all in Other liabilities	(16,847)	(17,004)	(18,524)
Amounts recognized in accumulated other comprehensive income (loss) ("AOCI"):
Prior service cost	0	0	0
Net actuarial loss	5,637	5,382	6,500
Total amount recognized in AOCI	5,637	5,382	6,500
Information for pension plans with an accumulated benefit obligation greater than plan assets:
Projected benefit obligation	16,847	17,004	18,524
Accumulated benefit obligation	16,847	17,004	18,524
Fair value of plan assets	$ 0	$ 0	$ 0