Acquisitions and disposition Disposition - additional information (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	$ 91,619,000	$ 86,545,000	$ 378,454,000	$ 321,419,000
Net Income (Loss) Attributable to Parent	3,180,000	3,879,000	25,995,000	23,104,000	32,787,000
BravePoint Group [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
DisposalGroupNotDiscontinuedOperationNetProceedsFromSale			12,000,000
DisposalGroupNotDiscontinuedOperationInvestmentIn	3,600,000		3,600,000
Revenues	5,500,000		15,100,000
Net Income (Loss) Attributable to Parent	268,000		(232,000)
Minimum [Member] | BravePoint Group [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal			6,500,000
Maximum [Member] | BravePoint Group [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal			7,000,000
DisposalGroupNotDiscontinuedOperationGainLossOnDisposalNetOfTax			$ 4,000,000