Costs And Estimated Earnings On Uncompleted Contracts (Narrative) (Details)	3 Months Ended	12 Months Ended
Mar. 31, 2012	Dec. 31, 2011
Costs And Estimated Earnings On Uncompleted Contracts [Abstract]
Costs and estimated earnings in excess of billings on uncompleted contracts, net of billings in excess of costs and estimated earnings, percentage	88.50%	91.40%
Number of significant customers	5	5

Costs And Estimated Earnings In Excess Of Billings On Uncompleted Contracts Net

No definition available.

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Namespace Prefix:	sbac_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration