CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net income	$ 14,044	$ 25,003
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	64,198	64,255
Non-cash interest expense	679	614
Non-cash stock compensation expense	15,021	18,085
Non-cash income tax provision (benefit)	1,026	(100)
Non-cash amortization on investments	(327)	1,171
Changes in assets and liabilities, net of effects from acquisitions of businesses:
Accounts receivable, net	(51,544)	(179,350)
Pharmaceutical inventory	(4,793)	(9,388)
Other assets	(23,890)	(57,398)
Accounts payable and accrued liabilities	20,821	50,322
Medical claims payable and other medical liabilities	4,329	89,932
Contingent consideration	(3,758)	303
Tax contingencies	610	721
Deferred credits and other long-term liabilities	(7,429)	16,884
Other	372	69
Net cash provided by operating activities	29,359	21,123
Cash flows from investing activities:
Capital expenditures	(27,804)	(37,132)
Acquisitions and investments in businesses, net of cash acquired	(320)
Purchases of investments	(295,768)	(334,250)
Proceeds from maturities and sales of investments	288,290	227,446
Net cash used in investing activities	(35,602)	(143,936)
Cash flows from financing activities:
Payments to acquire treasury stock	(4,124)	(14,323)
Proceeds from exercise of stock options	20,647	21,476
Payments on debt, finance lease and deferred financing obligations	(15,543)	(33,912)
Payments on contingent consideration	(6,247)
Other	(446)	(3,051)
Net cash used in financing activities	(5,713)	(29,810)
Net decrease in cash and cash equivalents	(11,956)	(152,623)
Cash and cash equivalents at beginning of period	272,308	398,732
Cash and cash equivalents at end of period	260,352	246,109
Non-cash investing activities:
Assets acquired under finance leases and deferred financing	$ 3,302	$ 4,623