Employee Pension Benefits (Schedule Of Components Of Net Periodic Pension Benefit Of The ESI Pension Plan And ESI Excess Pension Plan) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Employee Pension Benefits [Abstract]
Interest cost	$ 530	$ 598
Expected return on assets	(1,147)	(1,147)
Recognized net actuarial loss	695	476
Amortization of prior service (credit)	(388)	(346)
Net periodic pension (benefit)	$ (310)	$ (419)