CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 21,735	$ 61,458
Cash held in trust	5,268	5,122
Accounts receivable, less allowance for doubtful accounts of $1,465 and $1,306	419,355	361,044
Expenditures billable to clients	40,615	44,012
Other current assets	53,872	37,109
Total Current Assets	540,845	508,745
Fixed assets, at cost, less accumulated depreciation of $101,117 and $96,554	73,868	63,557
Investments in non-consolidated affiliates	5,159	6,263
Goodwill	868,483	870,301
Other intangible assets, net	92,975	72,382
Deferred tax asset	21,774	15,367
Other assets	39,208	41,010
Total Assets	1,642,312	1,577,625
Current Liabilities:
Accounts payable	331,330	359,568
Trust Liability, Current	5,268	5,122
Accruals and other liabilities	255,282	297,964
Advance billings	148,352	119,100
Current portion of long-term debt	260	470
Current portion of deferred acquisition consideration	119,506	130,400
Total Current Liabilities	859,998	912,624
Long-term debt, less current portion	951,187	728,413
Long-term portion of deferred acquisition consideration	123,591	216,704
Other liabilities	52,293	44,905
Deferred tax liabilities	106,950	92,581
Total Liabilities	2,094,019	1,995,227
Redeemable Noncontrolling Interests (Note 2)	60,174	69,471
Commitments, Contingencies and Guarantees (Note 11)
Shareholders’ Deficit:
Charges in excess of capital	(310,273)	(315,261)
Accumulated deficit	(582,640)	(526,990)
Total Shareholders' Deficit	(511,881)	(487,073)
Total Liabilities, Redeemable Noncontrolling Interests and Shareholders’ Deficit	1,642,312	1,577,625
Common Class A
Shareholders’ Deficit:
Class A Shares, no par value, unlimited authorized, 50,253,153 and 49,986,705 shares issued and outstanding in 2016 and 2015	315,368	269,841
Class B Shares, no par value, unlimited authorized, 3,755 shares issued and outstanding in 2016 and 2015, each convertible into one Class A share	315,368	269,841
Common Class B
Shareholders’ Deficit:
Class A Shares, no par value, unlimited authorized, 50,253,153 and 49,986,705 shares issued and outstanding in 2016 and 2015	1	1
Class B Shares, no par value, unlimited authorized, 3,755 shares issued and outstanding in 2016 and 2015, each convertible into one Class A share	1	1
Share Capital To Be Issued [Member]
Common Stock, Value, To be Issued	2,360
Shareholders’ Deficit:
Total Shareholders' Deficit		0
Share Capital To Be Issued [Member] | Common Class A
Common Stock, Value, To be Issued	2,360	0
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
Shareholders’ Deficit:
Accumulated other comprehensive income (loss)	(3,406)	6,257
Total Shareholders' Deficit	(3,406)	6,257
Parent [Member]
Shareholders’ Deficit:
Stockholders' Equity Attributable to Parent	(578,590)	(566,152)
Total Shareholders' Deficit	(578,590)	(566,152)
Noncontrolling Interest [Member]
Shareholders’ Deficit:
Noncontrolling Interests	66,709	79,079
Total Shareholders' Deficit	$ 66,709	$ 79,079