Segment Information (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net Income (Loss) Attributable to Parent	$ 11,253	$ 834	$ 687	$ (22,797)
Depreciation, Depletion and Amortization, Nonproduction	10,766	11,436	21,664	22,656
Share-based Compensation	5,540	5,530	10,490	10,215
Revenue	390,532	337,047	735,232	646,089
Income (Loss) from Equity Method Investments	641	(290)	502	(61)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	13,467	2,088	3,784	(20,684)
Net Income (Loss) Attributable to Noncontrolling Interest	2,214	1,254	3,097	2,113	$ 5,218
Cost of Services	267,822	228,835	505,385	440,281
General and Administrative Expense	85,563	72,709	173,403	150,537
Operating Income (Loss)	26,381	24,067	34,780	32,615
Other Nonoperating Income (Expense)	6,596	26	9,163	15,538
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	17,467	7,122	11,892	(17,513)
Income Tax Expense (Benefit)	4,641	4,744	8,610	3,110
Income Loss From Continuing Operations Before Equity In Earnings Of Non-consolidated Affiliates	12,826	2,378	3,282	(20,623)
Payments to Acquire Property, Plant, and Equipment		7,909	21,156	13,448
United States [Member]
Segment Reporting Information [Line Items]
Revenue	304,463	272,992	579,145	525,190
Canada [Member]
Segment Reporting Information [Line Items]
Revenue	30,583	33,614	57,053	62,020
Other Regions [Member]
Segment Reporting Information [Line Items]
Revenue	55,486	30,441	99,034	58,879
Domestic Creative Agencies [Member]
Segment Reporting Information [Line Items]
Payments to Acquire Property, Plant, and Equipment		463
Specialized Communications [Member]
Segment Reporting Information [Line Items]
Depreciation, Depletion and Amortization, Nonproduction		2,476
Operating Income (Loss)		4,428
Media Services [Member]
Segment Reporting Information [Line Items]
Depreciation, Depletion and Amortization, Nonproduction	1,011	1,057	2,016	2,099
Share-based Compensation	154	58	314	117
Revenue	35,695	31,373	70,939	62,200
Operating Income (Loss)	3,555	1,753	6,197	3,044
Payments to Acquire Property, Plant, and Equipment	$ 271	337	$ 1,284	$ 626
All Other [Member]
Segment Reporting Information [Line Items]
Revenue		78,312
Payments to Acquire Property, Plant, and Equipment		$ 1,340