CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Net income (loss)	$ (3,465)	$ 44,869	$ 29,734
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	19,967	15,111	12,495
Amortization	58,565	55,261	27,563
Amortization of debt issuance costs	3,311	3,312	3,014
Impairment loss	2,778	1,799	0
Property and equipment write-off	681	1,004	104
Excess tax benefit from stock-based compensation	(8,528)	(28,406)	(19,585)
Stock-based compensation expense	34,537	28,267	41,549
Deferred income tax benefit, net	(5,792)	(1,366)	(12,740)
Provision for losses on accounts receivable	7,002	4,822	2,317
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(3,999)	(12,353)	(6,607)
Income taxes payable	11,380	24,542	29,295
Prepaid expenses and other current assets	367	(2,846)	2,934
Deposits and other assets	686	(157)	399
Accounts payable and other liabilities	9,938	6,078	(3,882)
Deferred revenue	3,817	3,972	1,708
Net cash provided by operating activities	131,245	143,909	108,298
Investing activities:
Proceeds from sale and settlement of investments	1,900	5,675	76
Purchases of property and equipment and other assets	(35,061)	(27,444)	(19,042)
Acquisitions, net of cash acquired	(182,341)	(584,218)	0
Net cash used in investing activities	(215,502)	(605,987)	(18,966)
Financing activities:
Proceeds from long-term debt	0	550,000	0
Payments of long-term debt	(20,000)	(318,125)	(17,500)
Payments of debt issuance costs	0	(9,969)	0
Payments of deferred consideration	0	(1,344)	(1,344)
Excess tax benefit from stock-based compensation	8,528	28,406	19,585
Repurchase of restricted stock to satisfy tax withholding obligations	(16,436)	(50,555)	(8,469)
Proceeds from equity offering, net of transaction costs	0	529,360	0
Proceeds from exercise of stock options and employee stock purchase plan	7,404	5,740	18,133
Net cash provided by (used in) financing activities	(20,504)	733,513	10,405
Effect of foreign currency exchange rates on cash and cash equivalents	(433)	(376)	189
Net increase (decrease) in cash and cash equivalents	(105,194)	271,059	99,926
Cash and cash equivalents at beginning of year	527,012	255,953	156,027
Cash and cash equivalents at end of year	$ 421,818	$ 527,012	$ 255,953