Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities:
Net income	$ 19,295	$ 48,742
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of property, equipment and software	16,333	15,989
Amortization of intangible assets	7,416	4,677
Amortization of deferred financing costs	282	282
Stock-based compensation expense	17,950	15,781
Deferred income taxes	(196)	4,588
Noncash lease expense	2,456	2,366
Release of estimated liability for appeals, net	0	(10,478)
Changes in operating assets and liabilities:
Accounts receivable	13,040	(2,062)
Prepaid expenses and other current assets	4,778	(363)
Other assets	(8,471)	(1,200)
Income taxes receivable	1,980	9,386
Accounts payable, accrued expenses and other liabilities	(8,603)	(7,235)
Operating lease liabilities	(2,467)	(2,952)
Liability for appeals	1,968	605
Net cash provided by operating activities	65,761	78,126
Investing activities:
Acquisition of a business, net of cash acquired	1,530	0
Purchases of property and equipment	(3,143)	(945)
Investment in capitalized software	(8,359)	(7,465)
Net cash used in investing activities	(9,972)	(8,410)
Financing activities:
Proceeds from exercise of stock options	1,619	26,998
Payments of tax withholdings on behalf of employees for net-share settlements	(3,460)	(6,947)
Payments on capital lease obligations	(145)	(36)
Net cash (used in)/provided by financing activities	(1,986)	20,015
Net increase in cash and cash equivalents	53,803	89,731
Cash and Cash Equivalents
Cash and cash equivalents at beginning of year	139,268	178,946
Cash and cash equivalents at end of period	193,071	268,677
Supplemental disclosure of cash flow information:
Cash paid for income taxes/(refunds received), net of refunds	1,107	(6,509)
Cash paid for interest	2,319	5,524
Supplemental disclosure of non-cash activities:
Change in balance of accrued property and equipment purchases	$ (2,476)	$ 250