Pension Plans and Other Postretirement Benefits (Details 2) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Amortization of:
Total recognized in other comprehensive income (loss)		$ (1,815)	$ 1,810	$ (5,645)
Weighted-average assumptions used to determine expense:
Discount rate			4.46%	3.51%
Expected return on plan assets	[1]		0.00%	0.00%
Weighted-average assumptions used to determine benefit obligations as of December 31:
Discount rate			3.66%	4.46%
Expected return on plan assets	[1]		0.00%	0.00%
Defined Benefit Plan [Member]
Service cost:
Benefit accrual		0	$ 0	$ 0
Other expenses		450	360	360
Interest cost		1,189	1,679	1,369
Expected return on plan assets		(1,875)	(2,402)	(2,238)
Settlement loss		0	2,668	867
Amortization of:
Prior service cost		0	0	0
Actuarial loss		1,626	1,371	1,602
Net periodic pension expense		1,390	3,676	1,960
Changes in plan assets and benefit obligations included in other comprehensive income (loss):
Prior service cost		0	0	0
Net actuarial loss (gain)		930	(1,037)	(1,888)
Amortization of:
Prior service cost		0	0	0
Actuarial loss		(1,626)	(1,371)	(1,602)
Total recognized in other comprehensive income (loss)		$ (696)	$ (2,408)	$ (3,490)
Weighted-average assumptions used to determine expense:
Discount rate		3.66%	4.46%	3.51%
Expected return on plan assets		6.75%	7.50%	7.50%
Annual rate of salary increase	[1]
Weighted-average assumptions used to determine benefit obligations as of December 31:
Discount rate		4.20%	3.66%	4.46%
Expected return on plan assets		6.75%	7.50%	7.50%
Annual rate of salary increase	[1]
Supplemental Defined Benefit Plans [Member]
Service cost:
Benefit accrual		$ 0	$ 0	$ 0
Other expenses		0	0	0
Interest cost		654	716	616
Expected return on plan assets		0	0	0
Settlement loss		0	0	0
Amortization of:
Prior service cost		0	0	124
Actuarial loss		273	157	203
Net periodic pension expense		927	873	943
Changes in plan assets and benefit obligations included in other comprehensive income (loss):
Prior service cost		0	0	0
Net actuarial loss (gain)		(845)	2,431	(783)
Amortization of:
Prior service cost		0	(2)	(124)
Actuarial loss		(273)	(157)	(203)
Total recognized in other comprehensive income (loss)		$ (1,118)	$ 2,272	$ (1,110)
Weighted-average assumptions used to determine expense:
Discount rate		3.66%	4.46%	3.51%
Expected return on plan assets	[1]
Annual rate of salary increase	[1]
Weighted-average assumptions used to determine benefit obligations as of December 31:
Discount rate		4.20%	3.66%	4.46%
Expected return on plan assets	[1]
Annual rate of salary increase	[1]

[1] Not applicable.