Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 97,213	$ 42,466
Adjustments to reconcile net income to net cash provided by operating activities:
Asset impairment	612
Depreciation and amortization expense	10,785	6,752
Bad debt expense	36,706	32,028
Compensation expense related to share-based awards	9,735	3,922
Deferred income taxes	11,339	16,265
Changes in operating assets and liabilities	(28,637)	(16,042)
Net cash provided by operating activities	137,753	85,391
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of available-for-sale investments	(333,767)	(418,156)
Sales of available-for-sale investments	213,576	382,022
Purchases of property and equipment	(7,479)	(3,220)
Business acquisition	(39,819)
Other		9
Net cash used in investing activities	(167,489)	(39,345)
CASH FLOWS FROM FINANCING ACTIVITIES:
Issuance of common stock	1,925	1,326
Purchase of treasury stock	(17,862)
Payments of employee tax associated with stock compensation	(894)	(2,692)
Net cash used in financing activities	(16,831)	(1,366)
NET (DECREASE) INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(46,567)	44,680
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, beginning of the period	108,687	32,731
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, end of the period	62,120	$ 77,411
Supplemental non-cash disclosure:
Amount held in escrow to secure indemnification obligations from business acquisition	$ 4,000