CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net loss	$ (9,683)	$ (22,434)
Adjustments to reconcile net loss to cash used in operating activities:
Stock-based compensation	4,950	4,685
Depreciation	5,600	5,028
Amortization of intangibles	5,298	6,192
Amortization of deferred finance charges	742	7,021
Adjustment to deferred acquisition consideration	11,460	6,440
Deferred income tax	1,906	(2,266)
Loss on sale of assets	21	0
Losses (earnings) of non-consolidated affiliates	139	(229)
Other non-current assets and liabilities	(5,658)	(1,482)
Foreign exchange	(1,370)	(14,134)
Changes in working capital:
Accounts receivable	(39,855)	(31,586)
Expenditures billable to clients	(3,953)	21,692
Prepaid expenses and other current assets	(4,270)	(13,030)
Accounts payable, accruals and other liabilities	(10,757)	(132,202)
Advance billings	14,754	17,016
Net cash used in operating activities	(30,676)	(122,416)
Cash flows used in investing activities:
Capital expenditures	(9,413)	(5,539)
Deposits	(1,627)	0
Acquisitions, net of cash acquired	0	(1,774)
Distributions from non-consolidated affiliates	(50)	(815)
Net Cash Provided by (Used in) Investing Activities	(11,090)	(8,128)
Cash flows provided by financing activities:
Acquisition related payments	(5,183)	(30,479)
Repayment of long-term debt	(135)	(156)
Purchase of shares	(51)	(902)
Premium paid on redemption of notes	0	(26,873)
Deferred financing costs	0	(18,091)
Distributions to noncontrolling interests	(2,471)	(2,399)
Payment of dividends	(22)	(10,636)
Net Cash Provided by (Used in) Financing Activities	37,089	92,443
Effect of exchange rate changes on cash and cash equivalents	(58)	(1,517)
Decrease in cash and cash equivalents	(4,735)	(39,618)
Cash and cash equivalents at beginning of period	27,921	61,458
Cash and cash equivalents at end of period	23,186	21,840
Supplemental disclosures:
Cash income taxes paid	1,293	143
Cash interest paid	999	25,703
Change in cash held in trusts	36	208
Non-cash transactions:
Capital leases	393	156
Dividends payable	716	1,115
Deferred acquisition consideration settled through issuance of shares	4,153
Six Point Seven Five Percentage Notes [Member]
Adjustments to reconcile net loss to cash used in operating activities:
Loss on redemption of notes	0	26,873
Cash flows provided by financing activities:
Repayment of 6.75% Notes	0	735,000
Six Point Five Zero Percentage Notes [Domain]
Cash flows provided by financing activities:
Proceeds from issuance of 6.50% Notes	0	900,000
Wells Fargo Capital Finance, LLC | Revolving Credit Facility [Member]
Cash flows provided by financing activities:
Repayments of revolving credit agreement	(381,500)	(217,208)
Proceeds from revolving credit agreement	331,961	234,187
Common Stock [Member]
Non-cash transactions:
Deferred acquisition consideration settled through issuance of shares	5,028
Series 4 Convertible Preferred Stock [Domain]
Cash flows provided by financing activities:
Proceeds from issuance of convertible preference shares	95,000	0
Series 4 Convertible Preferred Stock [Domain] | Convertible Preferred Stock [Member]
Non-cash transactions:
Convertible preference shares issuance costs payable	4,270	0
Convertible Preferred Stock [Member]
Cash flows provided by financing activities:
Convertible preference shares issuance costs	$ (510)	0
Common Class A [Member] | Common Stock [Member]
Non-cash transactions:
Deferred acquisition consideration settled through issuance of shares		$ 0