CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 128,320	$ 117,956
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization	43,220	43,248
Depreciation	10,672	10,420
Non-cash stock-based compensation	6,674	12,459
Change in estimated acquisition earn-out payables	3,236	1,735
Deferred income taxes	15,907	10,745
Amortization of debt discount	79	79
Deferred Finance Costs, Own-share Lending Arrangement, Issuance Costs, Amortization Expense	807	804
Accretion (Amortization) of Discounts and Premiums, Investments	47	0
Income tax benefit from exercise of shares from the stock benefit plans	(6,816)	(1,827)
Payments On Acquisition Earn Outs In Excess Of Original Estimated Payables	3,550	2,778
Net gain on sales of investments, fixed assets and customer accounts	(2,700)	(478)
Changes in operating assets and liabilities, net of effect from acquisitions and divestitures:
Restricted cash and investments (increase) decrease	(47,893)	13,876
Premiums, commissions and fees receivable (increase) decrease	(34,099)	11,109
Reinsurance recoverables (increase)	(28,844)	(66,174)
Prepaid reinsurance premiums decrease	10,736	18,008
Other assets (increase)	(11,272)	(20,872)
Premiums payable to insurance companies increase	90,068	36,851
Premium deposits and credits due customers increase	12,049	2,211
Losses and loss adjustment reserve increase	28,844	66,174
Unearned premiums (decrease)	(10,736)	(18,008)
Accounts payable increase	34,156	16,375
Accrued expenses and other liabilities (decrease)	(29,765)	(21,935)
Other liabilities (decrease)	(18,346)	(2,594)
Net cash provided by operating activities	190,794	227,384
Cash flows from investing activities:
Additions to fixed assets	(8,944)	(8,597)
Payments for businesses acquired, net of cash acquired	(107,290)	(105,056)
Proceeds from sales of fixed assets and customer accounts	3,291	3,998
Purchases and proceeds from sales of investments	(7,026)	(913)
Net cash used in investing activities	(119,969)	(110,568)
Cash flows from financing activities:
Payments on acquisition earn-outs	(7,012)	(11,261)
Payments on long-term debt	(20,625)	(31,875)
Income tax benefit from exercise of shares from the stock benefit plans	6,816	1,827
Issuances of common stock for employee stock benefit plans	916	500
Repurchase Of Stock Benefit Plan Shares For Employees To Fund Tax Withholdings	6,273	2,168
Purchase of treasury stock	(11,250)	(85,000)
Settlement (Prepayment) of accelerated share repurchase program	11,250	(15,000)
Cash dividends paid	(34,128)	(31,280)
Net cash (used in) financing activities	(60,306)	(174,257)
Net increase (decrease) in cash and cash equivalents	10,519	(57,441)
Cash and cash equivalents at beginning of period	443,420
Cash and cash equivalents at end of period	$ 453,939	$ 412,607