Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Mar. 25, 2015	Jun. 30, 2014
Document Information [Line Items]
Entity Registrant Name	Global Defense & National Security Systems, Inc.
Entity Central Index Key	0001583513
Current Fiscal Year End Date	--12-31
Entity Filer Category	Smaller Reporting Company
Trading Symbol	GDEF
Entity Common Stock, Shares Outstanding		9,624,725
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2014
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2014
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 70,587,000