Employee Benefit Plans (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Pension Plans Defined Benefit Member
Defined Benefit Plan Disclosure
Defined Benefit Plan Service Cost	$ 1,597	$ 1,406	$ 3,012	$ 2,492
Defined Benefit Plan Interest Cost	1,052	810	1,942	1,723
Defined Benefit Plan Expected Return On Plan Assets	825	803	1,469	1,289
Defined Benefit Plan Amortization Of Prior Service Cost Credit	94	8	101	15
Defined Benefit Plan Amortization Of Gains Losses	(314)	64	(502)	(375)
Total	2,232	1,357	4,088	3,316
Other Postretirement Benefit Plans Defined Benefit Member
Defined Benefit Plan Disclosure
Defined Benefit Plan Service Cost	212	149	424	298
Defined Benefit Plan Interest Cost	221	168	441	337
Defined Benefit Plan Expected Return On Plan Assets	0	0	0	0
Defined Benefit Plan Amortization Of Prior Service Cost Credit	0	0	0	0
Defined Benefit Plan Amortization Of Gains Losses	(59)	(5)	(118)	(10)
Total	$ 492	$ 322	$ 983	$ 645