Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities
Net income	$ 127,021	$ 114,616
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	17,232	14,066
Stock-based compensation expense	11,551	10,989
Deferred taxes	162	326
Other	2,005	1,290
Changes in operating assets and liabilities:
(Increase) in accounts receivable	(9,560)	(12,535)
Decrease (increase) in prepaid expenses and other assets	97	(4,503)
(Decrease) in accrued employee compensation	(5,034)	(3,756)
(Decrease) in income and other tax liabilities	(755)	(3,277)
Increase in deferred revenue	1,125	676
Increase (decrease) in accounts payable, accrued expenses and other liabilities	4,614	(2,917)
Net cash provided by operating activities	153,812	121,583
Cash flows from investing activities
Proceeds from maturities and sales, available-for-sale investments	256,301	146,295
Purchases, available-for-sale investments	(260,318)	(196,810)
Purchases of furniture, equipment and leasehold improvements	(23,821)	(7,245)
Capitalization of software development costs	(9,171)	(10,094)
Other	25	(53)
Net cash (used in) investing activities	(36,984)	(67,907)
Cash flows from financing activities
Cash dividend on common stock	(46,893)	(36,717)
Exercise of stock options	1,387	1,640
Withholding tax payments on restricted stock vesting and stock option exercises	(7,940)	(12,906)
Repurchases of common stock	(18,985)	(36,352)
Net cash (used in) financing activities	(72,431)	(84,335)
Effect of exchange rate changes on cash and cash equivalents	(1,326)	1,408
Cash and cash equivalents
Net increase (decrease) for the period	43,071	(29,251)
Beginning of period	167,014	168,243
End of period	210,085	138,992
Corporate Debt [Member]
Changes in operating assets and liabilities:
Decrease (Increase) in trading securities	6,671	8,338
Mutual Funds Held In Rabbi Trust [Member]
Changes in operating assets and liabilities:
Decrease (Increase) in trading securities	$ (1,317)	$ (1,730)

No definition available.

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- Definition

For the entity and the disposal group, cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits are not generally reported as cash and cash equivalents.

+ References

No definition available.