Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended		5 Months Ended	6 Months Ended
	Jan. 24, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2011	Jun. 30, 2012
Qualified Pension [Member]
Schedule of net periodic benefit cost related to pension and post-retirement healthcare
Service cost	$ 849	$ 4,096	$ 3,177	$ 5,295	$ 8,192
Interest cost	934	3,637	3,655	6,092	7,299
Expected return on plan assets	(1,089)	(3,252)	(3,634)	(6,056)	(6,531)
Amortization of prior service cost	98
Amortization of actuarial loss	283	525			1,042
Plan Settlement					356
Net periodic benefit cost	1,075	5,006	3,198	5,331	10,358
Post-retirement Healthcare [Member]
Schedule of net periodic benefit cost related to pension and post-retirement healthcare
Service cost	1,167	6,784	4,310	7,183	13,568
Interest cost	1,252	6,183	4,813	8,022	12,365
Expected return on plan assets	(1)	(9)	(3)	(5)	(17)
Amortization of prior service cost	276
Amortization of actuarial loss	368	1,682			3,364
Net periodic benefit cost	$ 3,062	$ 14,640	$ 9,120	$ 15,200	$ 29,280