Segment Information Reportable Segment Information (Reconciliation of Total Segment Operating Income to Consolidated Operating Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Total revenues	$ 273,174	$ 211,800	$ 527,843	$ 412,302
Direct Costs By Segment	204,945	147,822	406,822	290,360
Income from operations	58,560	58,945	106,535	112,283
Global Operating Costs	9,678	5,078	14,502	9,750
Depreciation, Depletion and Amortization, Nonproduction	39,903	31,059	79,225	58,233
Business Cloud Services Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	144,709	142,460	286,254	280,599
Direct Costs By Segment	86,610	89,987	171,854	177,849
Income from operations	58,099	52,473	114,400	102,750
Depreciation, Depletion and Amortization, Nonproduction	17,189	21,251	33,953	38,752
Business Cloud Services Segment [Member] | Cloud Connect [Member]
Segment Reporting Information [Line Items]
Total revenues	95,667	92,858	189,300	183,102
Income from operations	44,942	42,574	89,381	83,094
Depreciation, Depletion and Amortization, Nonproduction	6,081	7,575	11,963	13,145
Business Cloud Services Segment [Member] | Cloud Services [Member]
Segment Reporting Information [Line Items]
Total revenues	47,763	48,509	94,476	95,228
Income from operations	13,375	10,650	25,791	21,624
Depreciation, Depletion and Amortization, Nonproduction	9,847	12,184	19,382	22,501
Business Cloud Services Segment [Member] | Intellectual Property [Member]
Segment Reporting Information [Line Items]
Total revenues	1,279	1,093	2,478	2,269
Income from operations	(218)	(751)	(772)	(1,968)
Depreciation, Depletion and Amortization, Nonproduction	1,261	1,492	2,608	3,106
Digital Media Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	128,474	69,385	241,605	131,794
Direct Costs By Segment	118,335	57,835	234,968	112,511
Income from operations	10,139	11,550	6,637	19,283
Depreciation, Depletion and Amortization, Nonproduction	22,714	9,808	45,272	19,481
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Total revenues	(9)	(45)	(16)	(91)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Income from operations	68,238	64,023	121,037	122,033
Depreciation, Depletion and Amortization, Nonproduction	$ 39,903	$ 31,059	$ 79,225	$ 58,233