Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 32,078	$ 30,753
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	4,882	4,002
Bad debt expense	13,715	13,719
Compensation expense related to share-based awards	2,416	3,753
Deferred income taxes	986	4,767
Changes in operating assets and liabilities	(31,923)	(12,286)
Net cash provided by operating activities	22,154	44,708
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of available-for-sale investments	(194,997)	(126,009)
Sales of available-for-sale investments	59,825	64,408
Purchases of property and equipment	(4,742)	(1,042)
Payments for potential business acquisition	(7,000)
Net cash used in investing activities	(146,914)	(62,643)
CASH FLOWS FROM FINANCING ACTIVITIES:
Issuance of common stock	659	314
Purchase of treasury stock	(3,828)
Payments of employee tax associated with stock compensation	(1,610)	(2,032)
Release of cash held in escrow	(3,986)
Net cash used in financing activities	(8,765)	(1,718)
NET DECREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(133,525)	(19,653)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, beginning of the period	325,178	109,684
CASH, CASH EQUIVALENTS AND RESTRICTED CASH, end of the period	$ 191,653	$ 90,031