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, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 73,730	$ 73,730
Accumulated Amortization	(27,640)	(26,141)
Net Carrying Amount	46,090	47,589
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	51,755	51,755
Accumulated Amortization	(20,812)	(19,585)
Net Carrying Amount	30,943	32,170
Useful Lives (in years)	11 years	11 years
Trade names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	15,400	15,400
Accumulated Amortization	(2,727)	(2,567)
Net Carrying Amount	12,673	12,833
Useful Lives (in years)	24 years	24 years
Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4,300	4,300
Accumulated Amortization	(1,827)	(1,720)
Net Carrying Amount	2,473	2,580
Useful Lives (in years)	10 years	10 years
Favorable leases [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,725	1,725
Accumulated Amortization	(1,724)	(1,719)
Net Carrying Amount	1	6
Useful Lives (in years)	3 years	3 years
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 years	2 years