LONG-TERM DEBT (Details - Covenant Calculations)	Apr. 01, 2014
Debt Disclosure [Abstract]
Maximum first lien secured leverage ratio after eight quarters after closing date	350.00%
Maximum total leverage ratio after eight fiscal quarters	450.00%

Maximum first lien secured leverage ratio after eight quarters after closing date.

No definition available.

Name:	csgp_Maximumfirstliensecuredleverageratioaftereightquartersafterclosingdate
Namespace Prefix:	csgp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant