Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Operating activities
Net income	$ 126,887	$ 41,074
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	24,548	23,768
Amortization and impairment of other intangible assets	6,297	7,797
Acquisition-related contingent consideration	355	1,547
Provision for doubtful accounts	11,951	10,510
Non-cash share-based compensation	12,219	12,888
Gain on sale of business	(13,031)	0
Amortization of debt discount and issuance costs	2,604	1,489
Other	751	297
Changes in operating assets and liabilities, net of effects from acquisitions:
Accounts receivable, billed and unbilled	(130,369)	(72,640)
Notes receivable	2,659	8,449
Prepaid expenses and other assets	(174)	935
Accounts payable, accrued expenses and other	16,150	16,823
Income taxes	28,922	8,876
Accrued compensation	7,207	(34,123)
Billings in excess of services provided	(10,704)	(3,657)
Net cash provided by operating activities	86,272	24,033
Investing activities
Proceeds from sale of business	50,283	0
Purchases of property and equipment	(27,841)	(20,021)
Other	741	74
Net cash provided by (used in) investing activities	23,183	(28,876)
Financing activities
Borrowings (repayments) under revolving line of credit, net	(100,000)	95,000
Proceeds from issuance of convertible notes	316,250	0
Payments of debt issue costs	8,048	0
Deposits	2,327	3,585
Purchase and retirement of common stock	(29,220)	(155,285)
Net issuance of common stock under equity compensation plans	31,241	(2,354)
Payments for acquisition-related contingent consideration	(3,029)	(79)
Net cash provided by (used in) financing activities	209,521	(59,133)
Effect of exchange rate changes on cash and cash equivalents	(3,070)	5,779
Net increase (decrease) in cash and cash equivalents	315,906	(58,197)
Cash and cash equivalents, beginning of period	189,961	216,158
Cash and cash equivalents, end of period	505,867	157,961
Supplemental cash flow disclosures
Cash paid for interest	13,428	12,424
Cash paid for income taxes, net of refunds	20,324	8,742
Non-cash investing and financing activities:
Issuance of stock units under incentive compensation plans	$ 1,059	$ 1,547

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets, combined with the amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of indefinite-lived intangible assets, other than goodwill, to fair value. As a noncash expense, this element is added back to net income when calculating cash provided by (used in) operations using the indirect method.

No definition available.