Amount of direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 24

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_BusinessAcquisitionCostOfAcquiredEntityTransactionCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Summary of significant accounting policies (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2012
Business combinations
Transaction costs associated with business combinations	$ 158	$ 0
Concourse Communications Detroit, LLC
Principles of consolidation
Percentage of ownership in subsidiaries	70.00%
Chicago Concourse Development Group, LLC
Principles of consolidation
Percentage of ownership in subsidiaries	70.00%
Boingo Holding Participacoes Ltda.
Principles of consolidation
Percentage of ownership in subsidiaries	75.00%