Employee Benefit Plans Fair Values of Pension Plan Assets, Classified in the Fair Value Hierarchy (Details) (Pension Plans, USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fixed income securities (2)	$ 187,172	[1]
Accounts payable – pending trades	(22)
Total	187,150		174,938		157,996
Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fixed income securities (2)	10,562	[1]
Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fixed income securities (2)	176,610	[1]
Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fixed income securities (2)	0	[1]
Fixed income securities
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fixed income securities (2)			182,643	[2]
Accounts payable – pending trades			(7,705)
Total			174,938
Fixed income securities | Level 1
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total			9,949	[2]
Fixed income securities | Level 2
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total			172,694	[2]
Fixed income securities | Level 3
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total			$ 0	[2]

[1] (1)Fixed income securities are comprised of corporate bonds (75%), government bonds (16%), government agencies securities (6%) and other fixed income securities (3%).

[2] (2)Fixed income securities are comprised of corporate bonds (74%), government bonds (16%), government agencies securities (7%) and other fixed income securities (3%).