CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 16,062	$ 61,458
Cash held in trust	5,345	5,122
Accounts receivable, less allowance for doubtful accounts of $1,465 and $1,306	421,270	361,044
Expenditures billable to clients	51,708	44,012
Other current assets	51,327	37,109
Total Current Assets	545,712	508,745
Fixed assets, at cost, less accumulated depreciation of $101,117 and $96,554	66,763	63,557
Investments in non-consolidated affiliates	6,392	6,263
Goodwill	876,644	870,301
Other intangible assets, net	61,418	72,382
Deferred tax asset	20,159	15,367
Other assets	39,065	41,010
Total Assets	1,616,153	1,577,625
Current Liabilities:
Accounts payable	308,909	359,568
Trust Liability, Current	5,345	5,122
Accruals and other liabilities	236,986	297,964
Advance billings	159,279	119,100
Current portion of long-term debt	361	470
Current portion of deferred acquisition consideration	102,985	130,400
Total Current Liabilities	813,865	912,624
Long-term debt, less current portion	987,381	728,413
Long-term portion of deferred acquisition consideration	129,059	216,704
Other liabilities	45,003	44,905
Deferred tax liabilities	98,191	92,581
Total Liabilities	2,073,499	1,995,227
Redeemable Noncontrolling Interests (Note 2)	65,367	69,471
Commitments, Contingencies and Guarantees (Note 11)
Shareholders’ Deficit:
Charges in excess of capital	(307,323)	(315,261)
Accumulated deficit	(549,110)	(526,990)
Total Shareholders' Deficit	(522,713)	(487,073)
Total Liabilities, Redeemable Noncontrolling Interests and Shareholders’ Deficit	1,616,153	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	275,882	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	275,882	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)	(6,227)	6,257
Total Shareholders' Deficit	(6,227)	6,257
Parent [Member]
Shareholders’ Deficit:
Stockholders' Equity Attributable to Parent	(584,417)	(566,152)
Total Shareholders' Deficit	(584,417)	(566,152)
Noncontrolling Interest [Member]
Shareholders’ Deficit:
Noncontrolling Interests	61,704	79,079
Total Shareholders' Deficit	$ 61,704	$ 79,079