Discontinued Operations - Additional Information (Details) - Discontinued Operations, Disposed of by Sale $ in Thousands		12 Months Ended
	Oct. 18, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 subsidiary
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of discontinued operation, net of tax				$ 14,000
Income tax (benefit) expense related to income from discontinued operations				10,100
Investor Force, Channel Intelligence, and Procurian
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of subsidiaries Sold | subsidiary					3
Investor Force
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of discontinued operation, net of tax				2,100
Channel Intelligence
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of discontinued operation, net of tax				5,800
Procurian
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of discontinued operation, net of tax				16,200
Income tax (benefit) expense related to income from discontinued operations				(1,200)
GovDelivery
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) on disposal of discontinued operation, net of tax		$ 11,100
Income tax (benefit) expense related to income from discontinued operations		$ 19,246	$ (64)	$ (2,403)
Consideration	$ 153,000
Proceeds from divestiture of businesses, net of cash divested	133,000
Additional amount of proceeds to be held in escrow subject to indemnifications claims	$ 10,000