Commitments And Contingencies (Standby Letters of Credit And Litigation) (Details) (Standby Letters Of Credit [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013 Quantity
Standby Letters Of Credit [Member]
Loss Contingencies [Line Items]
Number of irrevocable standby letters of credit	5
Maximum capacity to guarantee under existing letters of credit	$ 6.8
Irrevocable standby letters of credit, amount outstanding	$ 0
Letters of credit expiration date	Dec. 31, 2013

Maximum capacity to guarantee under all existing letters of credit without consideration of any amounts that could be guaranteed or the amounts currently outstanding under the letters of credit.

No definition available.

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Namespace Prefix:	cstr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration