Goodwill And Other Intangible Assets (Schedule Of Components Of Other Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2012 Y	Dec. 31, 2011 Y
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 73,730	$ 73,730
Accumulated Amortization	(21,529)	(19,981)
Net Carrying Amount	52,201	53,749
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	51,755	51,755
Accumulated Amortization	(15,903)	(14,676)
Net Carrying Amount	35,852	37,079
Useful Lives (in years)	11	11
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	15,400	15,400
Accumulated Amortization	(2,085)	(1,925)
Net Carrying Amount	13,315	13,475
Useful Lives (in years)	24	24
Software [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	550	550
Accumulated Amortization	(550)	(550)
Net Carrying Amount	0	0
Useful Lives (in years)	2	2
Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,300	4,300
Accumulated Amortization	(1,398)	(1,290)
Net Carrying Amount	2,902	3,010
Useful Lives (in years)	10	10
Favorable Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,725	1,725
Accumulated Amortization	(1,593)	(1,540)
Net Carrying Amount	$ 132	$ 185
Useful Lives (in years)	3	3