Discontinued Operations - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Discontinued Operations and Disposal Groups [Abstract]
Capital expenditures for discontinued operations	$ 2.7	$ 8.4

Disposal group including discontinued operation, capital expenditure.

No definition available.

Name:	dmd_DisposalGroupIncludingDiscontinuedOperationCapitalExpenditure
Namespace Prefix:	dmd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration