Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Operating activities
Net income	$ 38,945	$ 14,016
Adjustments to reconcile net income to net cash used in operating activities:
Depreciation and amortization	7,765	8,571
Amortization and impairment of other intangible assets	2,270	2,493
Acquisition-related contingent consideration	396	395
Provision for doubtful accounts	5,676	3,551
Non-cash share-based compensation	4,676	7,281
Non-cash interest expense and other	591	508
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable, billed and unbilled	(61,677)	(52,489)
Notes receivable	2,622	7,153
Prepaid expenses and other assets	(378)	553
Accounts payable, accrued expenses and other	9,348	287
Income taxes	13,480	3,650
Accrued compensation	(92,501)	(92,561)
Billings in excess of services provided	(413)	3,505
Net cash used in operating activities	(69,200)	(93,087)
Investing activities
Purchases of property and equipment	(7,680)	(5,831)
Other	27	127
Net cash used in investing activities	(7,653)	(5,704)
Financing activities
Borrowings under revolving line of credit, net	45,000	37,000
Deposits	1,431	3,069
Purchase and retirement of common stock	(14,220)	(36,918)
Net issuance of common stock under equity compensation plans	4,215	(812)
Payments for acquisition-related contingent consideration	(2,502)	0
Net cash provided by financing activities	33,924	2,339
Effect of exchange rate changes on cash and cash equivalents	5,012	1,253
Net decrease in cash and cash equivalents	(37,917)	(95,199)
Cash and cash equivalents, beginning of period	189,961	216,158
Cash and cash equivalents, end of period	152,044	120,959
Supplemental cash flow disclosures
Cash paid for interest	1,087	762
Cash paid for income taxes, net of refunds	1,688	4,246
Non-cash investing and financing activities:
Issuance of stock units under incentive compensation plans	$ 1,059	$ 1,547