Employee Benefit Plans (Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Amortization of unrecognized prior service cost	$ 21
Net periodic benefit cost	18,543	19,348	16,542
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	10,015	11,182	9,370
Interest cost	10,474	8,511	7,971
Expected return on plan assets	(11,288)	(8,495)	(7,743)
Amortization of actuarial loss from earlier periods	4,341	8,101	6,896
Amortization of unrecognized prior service cost	49	49	49
Settlement/Net loss recognition	4,953
Net periodic benefit cost	18,543	19,348	16,542
Other comprehensive income (loss) attributable to change from prior year	49,305	(32,552)
Total recognized in net periodic benefit cost and other comprehensive income (loss)	67,847	(13,204)
Post-Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,619	1,899	1,677
Interest cost	1,320	1,164	1,033
Amortization of unrecognized prior service cost	0
Settlement/Net loss recognition	257	739	432
Net periodic benefit cost	3,196	3,801	3,142
Other comprehensive income (loss) attributable to change from prior year	6,218	(3,779)
Total recognized in net periodic benefit cost and other comprehensive income (loss)	$ 9,414	$ 22