Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net income	$ 37,330	$ 69,878
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and software	24,121	24,719
Amortization of intangible assets	11,094	7,009
Amortization of deferred financing costs	423	423
Gain on sale of cost basis investment	0	(7,697)
Stock-based compensation expense	21,083	18,715
Deferred income taxes	(512)	6,327
Noncash lease expense	2,768	2,955
Release of estimated liability for appeals, net	0	(10,478)
Changes in operating assets and liabilities:
Accounts receivable	(8,678)	508
Prepaid expenses and other current assets	11,495	72
Other assets	(6,948)	(1,746)
Income taxes receivable	2,178	9,926
Accounts payable, accrued expenses and other liabilities	(91)	(3,976)
Operating lease liabilities	(2,905)	(3,927)
Liability for appeals	1,609	211
Net cash provided by operating activities	92,967	112,919
Investing activities:
Acquisition of a business, net of cash acquired	1,529	(36,554)
Proceeds from sale of cost basis investment	0	9,776
Purchases of property and equipment	(8,396)	(5,840)
Investment in capitalized software	(12,766)	(10,763)
Net cash used in investing activities	(19,633)	(43,381)
Financing activities:
Proceeds from exercise of stock options	2,145	39,175
Payments of tax withholdings on behalf of employees for net-share settlements	(3,484)	(6,970)
Payments on capital lease obligations	(229)	(93)
Net cash (used in)/provided by financing activities	(1,568)	32,112
Net increase in cash and cash equivalents	71,766	101,650
Cash and Cash Equivalents
Cash and cash equivalents at beginning of year	139,268	178,946
Cash and cash equivalents at end of period	211,034	280,596
Supplemental disclosure of cash flow information:
Cash paid for income taxes/(refunds received), net of refunds	7,035	(5,303)
Cash paid for interest	3,422	8,118
Supplemental disclosure of non-cash activities:
Change in balance of accrued property and equipment purchases	$ 1,159	$ 2,291