Pension and Other Postretirement Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Components of net periodic benefit cost [Abstract]
Defined benefit plans employer contributions toward sponsored pension plans	$ 5,000		$ 5,000
Anticipated contribution during current fiscal year			2,500
Aggregate contribution towards sponsored pension plans	7,500		7,500
Remeasurements	(1,380)		16,491
Pension Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost-benefits earned during the period	170	$ 270	526	$ 804
Interest cost on projected benefit obligation	2,297	2,624	7,021	7,975
Expected return on plan assets	(2,697)	(3,112)	(8,254)	(9,480)
Amortization of net transition (asset) obligation			0	0
Amortization of prior service (credit) cost	11	11	33	33
Amortization of (gain)/loss	304	57	935	158
Net periodic benefit cost	85	(150)	261	(510)
Other one-time charges	0	0	0	0
Total benefits cost (credited) charged to income	85	(150)	261	(510)
Other Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost-benefits earned during the period	97	80	301	252
Interest cost on projected benefit obligation	662	978	2,276	2,737
Expected return on plan assets	0	0	0	0
Amortization of net transition (asset) obligation			0	0
Amortization of prior service (credit) cost	(236)	(9)	(338)	(27)
Amortization of (gain)/loss	89	59	284	216
Net periodic benefit cost	612	1,108	2,523	3,178
Other one-time charges	0	435	0	435
Total benefits cost (credited) charged to income	$ 612	$ 1,543	$ 2,523	$ 3,613