Intangible Assets (Schedule Of Amortizable Intangible Assets Amortized At Annual Rate - AUC) (Details) (American University Of Caribbean [Member])	9 Months Ended
Mar. 31, 2012
American University Of Caribbean [Member]
Intangible Assets [Line Items]
2012	38.00%
2013	38.50%
2014	21.60%
2015	1.90%

Finite lived intangible assets amortized at annual rate, year three.

No definition available.

Name:	dv_FiniteLivedIntangibleAssetsAmortizedAtAnnualRateYearThree
Namespace Prefix:	dv_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration