Acquisitions (Narrative) (Details)			1 Months Ended		3 Months Ended				9 Months Ended
	May. 18, 2015 USD ($) shares	Jan. 08, 2015 USD ($) shares	Oct. 31, 2014 USD ($) shares	Jan. 31, 2014 USD ($)	Sep. 30, 2015 USD ($)	Dec. 31, 2014 USD ($) Company shares	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Sanbolic, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Preliminary consideration		$ 89,400,000
Cash acquired in business combination		200,000
Transaction costs		$ 500,000
Acquisition related costs							$ 0
Conversion of assumed non-vested stock units to shares of Company stock (shares) | shares		37,057
Grasshopper Group, LLC [Member]
Finite-Lived Intangible Assets [Line Items]
Preliminary consideration	$ 161,500,000
Cash acquired in business combination	3,600,000
Transaction costs	$ 300,000
Conversion of assumed non-vested stock units to shares of Company stock (shares) | shares	105,765
Framehawk, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Preliminary consideration				$ 24,200,000
Cash acquired in business combination				200,000
Transaction costs				$ 100,000
RightSignature, LLC [Member]
Finite-Lived Intangible Assets [Line Items]
Preliminary consideration			$ 37,800,000
Cash acquired in business combination			1,100,000
Transaction costs			$ 200,000
Conversion of assumed non-vested stock units to shares of Company stock (shares) | shares			67,500
Other 2014 Acquisition [Member]
Finite-Lived Intangible Assets [Line Items]
Preliminary consideration						$ 19,900,000		$ 17,200,000
Cash acquired in business combination						$ 200,000		800,000
Transaction costs								$ 100,000
Conversion of assumed non-vested stock units to shares of Company stock (shares) | shares						23,430
Number of privately-held companies acquired | Company						2
General and Administrative Expense [Member] | Sanbolic, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Acquisition related costs					$ 0				$ 200,000
General and Administrative Expense [Member] | Grasshopper Group, LLC [Member]
Finite-Lived Intangible Assets [Line Items]
Acquisition related costs					$ 0				$ 300,000
General and Administrative Expense [Member] | Framehawk, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Acquisition related costs										$ 100,000
General and Administrative Expense [Member] | RightSignature, LLC [Member]
Finite-Lived Intangible Assets [Line Items]
Acquisition related costs										100,000
General and Administrative Expense [Member] | Other 2014 Acquisition [Member]
Finite-Lived Intangible Assets [Line Items]
Acquisition related costs										$ 100,000