Employee Benefit Plans (Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	$ 16,542	$ 10,874	$ 10,783
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	9,370	7,548	6,944
Interest cost	7,971	7,702	7,052
Expected return on plan assets	(7,743)	(9,067)	(7,971)
Amortization of actuarial loss from earlier periods	6,896	3,367	2,467
Amortization of unrecognized prior service cost	49	49	49
Settlement/Net loss recognition		1,275	2,242
Net periodic benefit cost	16,542	10,874	10,783
Other comprehensive income (loss) attributable to change from prior year	7,017	42,487
Total recognized in net periodic benefit cost and other comprehensive income (loss)	23,559	53,361
Post-Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,677	1,165	1,017
Interest cost	1,033	934	849
Settlement/Net loss recognition	432	159	81
Net periodic benefit cost	3,142	2,258	1,947
Other comprehensive income (loss) attributable to change from prior year	3,715	2,823
Total recognized in net periodic benefit cost and other comprehensive income (loss)	$ 6,857	$ 5,081