Employee Benefits (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Pension Plan [Member]
Net periodic benefit cost
Service cost	$ 1,303	$ 1,575	$ 3,909	$ 4,725
Interest cost	1,468	1,295	4,404	3,883
Expected return on plan assets	(1,739)	(1,443)	(5,217)	(4,329)
Amortization of net loss	544	1,530	1,632	3,741
Net periodic benefit cost	1,576	2,957	4,728	8,020
Estimated 2014 pension plan contribution, disclosed in prior year 10K			1,156		6,260
Contribution by employer			7,416
Postretirement Benefit Plan [Member]
Net periodic benefit cost
Service cost	924	1,401	2,772	2,906
Interest cost	586	472	1,758	1,319
Expected return on plan assets	0	0	0	0
Amortization of net loss	224	385	672	659
Net periodic benefit cost	$ 1,734	$ 2,258	$ 5,202	$ 4,884