Segment Information Reportable Segment Information (Reconciliation of Total Segment Operating Income to Consolidated Operating Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting Information [Line Items]
Total revenues	$ 210,116	$ 178,701	$ 622,418	$ 515,992
Direct Costs By Segment	143,372	114,587	433,731	338,563
Income from operations	62,122	55,733	174,405	146,329
Global Operating Costs	4,667	8,428	14,418	31,269
Depreciation, Depletion and Amortization, Nonproduction	30,336	20,455	88,569	63,635
Business Cloud Services Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	143,342	126,436	423,941	369,685
Direct Costs By Segment	90,485	69,617	268,333	213,518
Income from operations	52,857	56,819	155,608	156,167
Depreciation, Depletion and Amortization, Nonproduction	20,218	12,961	58,971	41,733
Business Cloud Services Segment [Member] | Cloud Connect [Member]
Segment Reporting Information [Line Items]
Total revenues	92,599	89,511	275,700	264,987
Income from operations	43,503	48,346	126,598	136,909
Depreciation, Depletion and Amortization, Nonproduction	5,950	5,309	19,096	16,287
Business Cloud Services Segment [Member] | Cloud Services [Member]
Segment Reporting Information [Line Items]
Total revenues	49,624	35,819	144,853	100,050
Income from operations	10,350	9,459	31,974	21,808
Depreciation, Depletion and Amortization, Nonproduction	12,826	6,030	35,327	19,810
Business Cloud Services Segment [Member] | Intellectual Property [Member]
Segment Reporting Information [Line Items]
Total revenues	1,119	1,106	3,388	4,648
Income from operations	(996)	(986)	(2,964)	(2,550)
Depreciation, Depletion and Amortization, Nonproduction	1,442	1,622	4,548	5,636
Digital Media Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	66,819	52,312	198,613	146,476
Direct Costs By Segment	52,887	44,970	165,398	125,045
Income from operations	13,932	7,342	33,215	21,431
Depreciation, Depletion and Amortization, Nonproduction	10,118	7,280	29,598	21,303
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Total revenues	(45)	(47)	(136)	(169)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Income from operations	66,789	64,161	188,823	177,598
Depreciation, Depletion and Amortization, Nonproduction	$ 30,336	$ 20,241	$ 88,569	$ 63,036