Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 24,791	$ 17,502
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense	2,233	2,582
Bad debt expense	11,709	6,982
Compensation expense related to share-based awards	1,369	1,501
Deferred income taxes	6,778	3,704
Changes in operating assets and liabilities	(33,935)	(21,175)
Net cash provided by operating activities	12,945	11,096
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of available-for-sale investments	(138,700)	(50,799)
Sales of available-for-sale investments	135,062	49,257
Purchases of property and equipment	(479)	(1,360)
Net cash used in investing activities	(4,117)	(2,902)
CASH FLOWS FROM FINANCING ACTIVITIES:
Issuance of common stock	109	875
Payments of employee tax associated with stock compensation	(2,532)	(2,981)
Net cash used in financing activities	(2,423)	(2,106)
NET INCREASE IN CASH AND CASH EQUIVALENTS	6,405	6,088
CASH AND CASH EQUIVALENTS, beginning of the period	32,731	18,899
CASH AND CASH EQUIVALENTS, end of the period	$ 39,136	$ 24,987