Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Operating activities:
Net income	$ 23,204us-gaap_NetIncomeLoss	$ 18,712us-gaap_NetIncomeLoss
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,781us-gaap_DepreciationAndAmortization	1,488us-gaap_DepreciationAndAmortization
Equity-based compensation	3,078us-gaap_ShareBasedCompensation	2,274us-gaap_ShareBasedCompensation
Gain on disposal of equipment	(7)	(17)
Tax benefit of stock awards exercised/vested	6,601	6,547
Excess tax benefits from equity-based compensation	(6,579)	(6,509)
Deferred income taxes	1,730	1,302
Unrealized foreign currency (gain) loss	(97)	90
Changes in operating assets and liabilities:
Accounts receivable, net	2,440	4,496
Other assets	(2,024)	(4,447)
Accounts payable, accrued and other liabilities	(13,489)	(5,638)
Income taxes	(1,119)	(4,647)
Deferred revenue	(344)	5,493
Net cash provided by operating activities	15,175	19,144
Investing activities:
Purchase of property and equipment	(3,098)	(1,156)
Net purchases of investments	(1,279)	(427)
Net cash used in investing activities	(4,377)	(1,583)
Financing activities:
Purchase of common stock	(36,033)	(33,179)
Proceeds from issuance of common stock from options exercised	278	730
Excess tax benefits from equity-based compensation	6,579	6,509
Net cash used in financing activities	(29,176)	(25,940)
Foreign currency impact on cash	(241)	653
Net change in cash and cash equivalents	(18,619)	(7,726)
Cash and cash equivalents at beginning of period	115,708	124,375
Cash and cash equivalents at end of period	$ 97,089	$ 116,649

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Amount of gain (loss) on sale or disposal of property, plant and equipment assets, including oil and gas property and timber property.

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