Employee Benefits (Retirement Plans And Other Postretirement Benefits) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Retirement Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,100	$ 2,173	$ 8,514	$ 9,100
Interest cost	3,625	3,870	14,797	14,084
Expected return on plan assets	(4,947)	(4,680)	(18,966)	(17,513)
Amortization of prior service benefit	(888)	(259)	(3,535)	(187)
Amortization of net (gain) loss	2,750	1,773	9,830	10,196
Net periodic benefit cost (benefit)	2,640	2,877	10,640	15,680
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	875	700	3,020	3,443
Interest cost	1,025	1,125	4,363	4,906
Expected return on plan assets	(525)	(525)	(2,116)	(2,001)
Amortization of prior service benefit	(775)	(1,200)	(4,328)	(5,432)
Amortization of net (gain) loss	(500)	(650)	(2,521)	(1,276)
Net periodic benefit cost (benefit)	$ 100	$ (550)	$ (1,582)	$ (360)