CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities:
Net income	$ 29,734	$ 9,915	$ 14,656
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	12,495	10,053	8,435
Amortization	27,563	22,699	4,417
Amortization of debt issuance costs	3,014	1,989	0
Property and equipment write-off	104	122	628
Excess tax benefit from stock-based compensation	(19,585)	(198)	(2,541)
Stock-based compensation expense	41,549	12,282	8,103
Deferred consideration settlement	0	0	(1,207)
Deferred income tax expense (benefit), net	(12,740)	13,643	(17,104)
Provision for losses on accounts receivable	2,317	1,456	1,525
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(6,607)	1,295	(4,573)
Income taxes payable	29,295	7,598	7,992
Prepaid expenses and other current assets	2,934	(3,316)	1,046
Deposits and other assets	399	1,172	(154)
Accounts payable and other liabilities	(3,882)	1,629	2,228
Deferred revenue	1,708	5,787	4,334
Net cash provided by operating activities	108,298	86,126	27,785
Investing activities:
Proceeds from sale and settlement of investments	76	15,365	4,911
Proceeds from sale of building, net	0	0	83,553
Purchases of property and equipment and other assets	(19,042)	(14,834)	(15,013)
Acquisitions, net of cash acquired	0	(640,929)	(15,085)
Net cash provided by (used in) investing activities	(18,966)	(640,398)	58,366
Financing activities:
Proceeds from long-term debt	0	175,000	0
Payments of long-term debt	(17,500)	(4,375)	0
Payments of debt issuance costs	0	(11,546)	0
Payments of deferred consideration	(1,344)	0	(2,100)
Excess tax benefit from stock-based compensation	19,585	198	2,541
Repurchase of restricted stock to satisfy tax withholding obligations	(8,469)	(4,204)	(2,307)
Proceeds from equity offering, net of transaction costs	0	0	247,924
Proceeds from exercise of stock options and employee stock purchase plan	18,133	9,868	6,622
Net cash provided by financing activities	10,405	164,941	252,680
Effect of foreign currency exchange rates on cash and cash equivalents	189	78	44
Net increase (decrease) in cash and cash equivalents	99,926	(389,253)	338,875
Cash and cash equivalents at beginning of year	156,027	545,280	206,405
Cash and cash equivalents at end of year	$ 255,953	$ 156,027	$ 545,280