Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income (loss)	$ 7,775	$ (39,164)	$ 34,818
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense	20,230	16,162	17,318
Depreciation	55,948	52,742	37,853
Amortization of intangibles	52,302	43,983	15,236
Amortization of debt issuance costs and debt discount	4,598	3,138	0
Deferred income taxes	(3,276)	(12,495)	(6,665)
Restructuring expense, non-cash	0	7,075	0
Change in fair value of contingent consideration	115	7,212	(5,200)
Bargain purchase gain	0	0	(1,434)
Other	(877)	621	2,364
Changes in assets and liabilities:
Accounts receivable	(35,109)	3,280	(977)
Prepaid expenses and other current assets	(489)	(20,002)	3,346
Income taxes receivable	5,979	2,208	3,293
Other assets	(5,096)	(4,209)	(3,355)
Accounts payable and accrued expenses	10,608	(6,007)	8,252
Accrued compensation	9,329	9,292	3,030
Other current and non-current liabilities	(6,044)	19,891	(5,813)
Deferred revenue	(6,964)	6,674	(4,360)
Payment for acquisition-related contingent consideration	(2,549)	0	0
Net cash provided by operating activities	106,480	90,401	97,706
Cash flows from investing activities:
Maturities of short-term investments	6,964	96,588	174,416
Sales of short-term investments	0	161,772	1,175
Purchases of property and equipment	(22,809)	(25,505)	(32,565)
Investment in capitalized software	(36,130)	(39,469)	(32,977)
Acquisition, net of cash acquired of $0, $23,850 and $1,535, respectively	0	(1,082,740)	(3,490)
Net cash (used in) provided by investing activities	(51,975)	(889,354)	106,559
Cash flows from financing activities:
Repurchase of common stock	0	0	(93,586)
Proceeds from credit facility borrowings, net of discount	0	965,300	0
Repayment of credit facility borrowings	(59,800)	(238,700)	(30,000)
Payments for debt issuance costs	0	(18,269)	0
Proceeds from exercise of stock options	3,669	1,833	4,967
Finance lease liabilities paid	(2,393)	(1,201)	(113)
Tax payments for equity award issuances	(5,878)	(3,363)	(4,272)
Payment for acquisition-related contingent consideration	(12,600)	0	0
Net cash (used in) provided by financing activities	(77,002)	705,600	(123,004)
(Decrease) Increase in cash and cash equivalents	(22,497)	(93,353)	81,261
Cash and cash equivalents, beginning of period	115,591	208,944	127,683
Cash and cash equivalents, end of period	93,094	115,591	208,944
Supplemental cash flow disclosure:
Income taxes received, net	(4,588)	(4,136)	962
Interest paid	62,768	43,573	5,972
Non-cash transactions:
Accruals of purchases of property, equipment	3,156	12,097	7,924
Accruals for investment in capitalized software	1,948	1,495	2,711
Leasehold improvement paid by lessor	2,906	0	0
Acquisition consideration	$ 0	$ 84,156	$ 0