Employee Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Pension Benefits
Periodic costs for employee retirement benefit plans
Service Cost	$ 550	$ 446	$ 1,649	$ 1,181
Interest Cost	604	467	1,812	1,696
Expected Return on Assets	(615)	(314)	(1,844)	(1,712)
Amortization of Unrecognized Losses	387	441	1,162	424
Amortization of Unrecognized Prior Service Cost	2		7	7
Amortization of Transition Obligation		33
Net Periodic Benefit Cost	928	1,073	2,786	1,596
Other Benefits
Periodic costs for employee retirement benefit plans
Service Cost	394	326	1,338	979
Interest Cost	566	401	1,401	1,203
Expected Return on Assets	(571)	(256)	(943)	(769)
Amortization of Unrecognized Losses	141	219	1,324	658
Amortization of Unrecognized Prior Service Cost	2
Amortization of Transition Obligation		33	101	101
Net Periodic Benefit Cost	$ 532	$ 723	$ 3,221	$ 2,172