Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 88,356	$ 149,654
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization and depreciation	8,509	19,304
Asset impairment	1,884	0
Share-based compensation expense	13,735	15,700
Deferred income taxes	(10,044)	3,476
Excess tax benefit on share-based compensation	(5,190)	(1,354)
Net realized (gain) loss on investments	(2,169)	(2,236)
Other changes	20,506	15,926
Changes in assets and liabilities, net of effects of acquisitions and dispositions:
Premiums receivable and unearned premiums	611,783	(412,141)
Other current assets, receivables and noncurrent assets	(315,673)	(216,808)
Amounts receivable/payable under government contracts	(46,392)	33,597
Reserves for claims and other settlements	(138,096)	504,247
Accounts payable and other liabilities	373,134	188,343
Net cash provided by operating activities	600,343	297,708
CASH FLOWS FROM INVESTING ACTIVITIES:
Sales of investments	541,415	192,250
Maturities of investments	53,454	43,679
Purchases of investments	(1,314,248)	(228,437)
Purchases of property and equipment	(28,329)	(29,956)
Sales (purchases) of restricted investments and other	(5,640)	760
Net cash used in investing activities	(753,348)	(21,704)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from exercise of stock options and employee stock purchases	16,551	6,472
Excess tax benefit on share-based compensation	5,190	1,354
Repurchases of common stock	(111,978)	(12,518)
Borrowings under financing arrangements	225,000	0
Repayment of borrowings under financing arrangements	(115,000)	0
Net increase (decrease) in checks outstanding, net of deposits	8,230	0
Customer funds administered	12,676	(101,370)
Net cash provided by (used in) financing activities	40,669	(106,062)
Net (decrease) increase in cash and cash equivalents	(112,336)	169,942
Cash and cash equivalents, beginning of period	869,133	433,155
Cash and cash equivalents, end of period	756,797	603,097
SUPPLEMENTAL CASH FLOWS DISCLOSURE:
Interest paid	15,447	14,754
Income taxes paid	$ 133,160	$ 59,324