Acquisitions (Assets Acquired and Liabilities Assumed and Divested) (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Apr. 21, 2017	Jan. 10, 2017	Dec. 31, 2016	Apr. 27, 2016	Mar. 14, 2016	Jan. 07, 2016
Assets Acquired
Goodwill	$ 103,778			$ 69,097
RightAnswers, Inc. [Member]
Assets Acquired
Cash		$ 139
Accounts receivable		2,164
Other current assets		94
Property and equipment		158
Goodwill		20,238
Other assets		0
Total assets acquired		31,293
Liabilities Assumed
Accounts payable		(138)
Accrued expense and other		(1,317)
Deferred revenue		(5,540)
Total liabilities assumed		(6,995)
Total consideration		24,298
RightAnswers, Inc. [Member] | Customer Relationships [Member]
Assets Acquired
Intangible assets		5,700
RightAnswers, Inc. [Member] | Trade Name [Member]
Assets Acquired
Intangible assets		200
RightAnswers, Inc. [Member] | Technology [Member]
Assets Acquired
Intangible assets		$ 2,600
Omtool, Ltd [Member]
Assets Acquired
Cash			$ 2,957
Accounts receivable			784
Other current assets			405
Property and equipment			63
Goodwill			14,003
Other assets			33
Total assets acquired			25,985
Liabilities Assumed
Accounts payable			(219)
Accrued expense and other			(934)
Deferred revenue			(2,618)
Total liabilities assumed			(3,771)
Total consideration			22,214
Omtool, Ltd [Member] | Customer Relationships [Member]
Assets Acquired
Intangible assets			4,390
Omtool, Ltd [Member] | Trade Name [Member]
Assets Acquired
Intangible assets			170
Omtool, Ltd [Member] | Technology [Member]
Assets Acquired
Intangible assets			$ 3,180
API [Member]
Assets Acquired
Cash					$ 125
Accounts receivable					821
Other current assets					54
Property and equipment					68
Goodwill					3,420
Other assets					89
Total assets acquired					6,847
Liabilities Assumed
Accounts payable					(11)
Accrued expense and other					(137)
Deferred revenue					(1,699)
Total liabilities assumed					(1,847)
Total consideration					5,000
API [Member] | Customer Relationships [Member]
Assets Acquired
Intangible assets					1,420
API [Member] | Trade Name [Member]
Assets Acquired
Intangible assets					40
API [Member] | Technology [Member]
Assets Acquired
Intangible assets					$ 810
Hipcricket [Member]
Assets Acquired
Cash						$ 0
Accounts receivable						1,226
Other current assets						273
Property and equipment						0
Goodwill						8,531
Other assets						0
Total assets acquired						12,000
Liabilities Assumed
Accounts payable						(44)
Accrued expense and other						0
Deferred revenue						(356)
Total liabilities assumed						(400)
Total consideration						11,600
Hipcricket [Member] | Customer Relationships [Member]
Assets Acquired
Intangible assets						1,000
Hipcricket [Member] | Trade Name [Member]
Assets Acquired
Intangible assets						70
Hipcricket [Member] | Technology [Member]
Assets Acquired
Intangible assets						$ 900
LeadLander, Inc. [Member]
Assets Acquired
Cash							$ 365
Accounts receivable							199
Other current assets							55
Property and equipment							5
Goodwill							13,104
Other assets							6
Total assets acquired							16,184
Liabilities Assumed
Accounts payable							0
Accrued expense and other							(254)
Deferred revenue							(910)
Total liabilities assumed							(1,164)
Total consideration							15,020
LeadLander, Inc. [Member] | Customer Relationships [Member]
Assets Acquired
Intangible assets							970
LeadLander, Inc. [Member] | Trade Name [Member]
Assets Acquired
Intangible assets							70
LeadLander, Inc. [Member] | Technology [Member]
Assets Acquired
Intangible assets							$ 1,410