CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 106,770	$ 114,025
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	50,770	45,172
Non-cash interest expense	552	544
Non-cash stock compensation expense	14,764	13,935
Non-cash income tax expense (benefit)	(164)	12,395
Non-cash amortization on investments	7,273	5,373
Cash flows from changes in assets and liabilities, net of effects from acquisitions of businesses:
Restricted cash	17,987	(59,777)
Accounts receivable, net	(19,231)	604
Pharmaceutical inventory	(1,680)	(2,002)
Other assets	(9,781)	(4,218)
Accounts payable and accrued liabilities	6,685	(17,854)
Medical claims payable and other medical liabilities	16,144	37,422
Tax contingencies	(22,981)	(34,616)
Other	4,174	654
Net cash provided by operating activities	171,282	111,657
Cash flows from investing activities:
Capital expenditures	(42,091)	(53,049)
Purchase of investments	(235,946)	(197,525)
Maturity of investments	233,723	215,150
Other	(7,900)
Net cash used in investing activities	(52,214)	(35,424)
Cash flows from financing activities:
Payments to acquire treasury stock	(49,462)
Proceeds from exercise of stock options and warrants	24,548	13,092
Payments on capital lease obligations	(2,310)
Other	484	135
Net cash provided by (used in) financing activities	(26,740)	13,227
Net increase in cash and cash equivalents	92,328	89,460
Cash and cash equivalents at beginning of period	189,464	119,862
Cash and cash equivalents at end of period	281,792	209,322
Non-cash investing activities:
Property and equipment acquired under capital leases	$ 29,323