Employee Benefit Plans (Defined Benefit Plan) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Amounts recognized in accumulated other comprehensive income/(loss):
Net amount recognized in accumulated other comprehensive income/(loss)	$ 298,349		$ 298,349
Qualified Pension Plans
Value of plan assets:
Beginning fair value of plan assets			195,410
Expected return on plan assets			10,757
Plan settlements			(1,179)
Employer contributions			4,800
Benefits paid			(6,347)
Ending value of plan assets	203,441		203,441
Projected benefit obligation:
Beginning projected benefit obligation			408,216
Service cost	1,823	$ 4,075	5,169	$ 8,150
Interest cost	3,633	3,963	7,444	7,926
Plan amendment			(40,049)
Plan settlements			(569)
Benefits paid			(6,347)
Actuarial gain			4,768
Ending projected benefit obligation	369,096		369,096
Funded status	(165,655)		(165,655)
Accumulated benefit obligation	369,096		369,096
Amounts recognized in the consolidated balance sheet:
Long-term liabilities	165,655		165,655
Net amount recognized in the consolidated balance sheet	165,655		165,655
Amounts recognized in accumulated other comprehensive income/(loss):
Net prior service credit	38,842		38,842
Net actuarial loss	(118,251)		(118,251)
Plan settlements	(2)		(2)
Net amount recognized in accumulated other comprehensive income/(loss)	(79,411)		(79,411)
Post-retirement Healthcare Plans
Value of plan assets:
Beginning fair value of plan assets			0
Employer contributions			2,635
Benefits paid			(2,635)
Ending value of plan assets	0		0
Projected benefit obligation:
Beginning projected benefit obligation			741,372
Service cost	62	6,344	4,417	12,689
Interest cost	1,013	$ 7,311	5,678	$ 14,622
Plan amendment			(609,619)
Plan curtailment			(5,409)
Benefits paid			(2,635)
Actuarial gain			(27,075)
Ending projected benefit obligation	106,729		106,729
Funded status	(106,729)		(106,729)
Amounts recognized in the consolidated balance sheet:
Current liabilities	(5,166)		(5,166)
Long-term liabilities	101,563		101,563
Net amount recognized in the consolidated balance sheet	106,729		106,729
Amounts recognized in accumulated other comprehensive income/(loss):
Net prior service credit	529,422		529,422
Net actuarial loss	(173,382)		(173,382)
Net amount recognized in accumulated other comprehensive income/(loss)	$ 356,040		$ 356,040