CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 199,865	$ 185,383
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization	65,025	65,406
Depreciation	15,867	15,635
Non-cash stock-based compensation	11,593	17,348
Change in estimated acquisition earn-out payables	6,846	2,194
Deferred income taxes	20,081	16,974
Amortization of debt discount	118	118
Deferred Finance Costs, Own-share Lending Arrangement, Issuance Costs, Amortization Expense	1,207	0
Accretion (Amortization) of Discounts and Premiums, Investments	36	0
Income tax benefit from exercise of shares from the stock benefit plans	(7,213)	(2,502)
Payments On Acquisition Earn Outs In Excess Of Original Estimated Payables	3,683	4,917
Net gain on sales of investments, fixed assets and customer accounts	(2,860)	(830)
Changes in operating assets and liabilities, net of effect from acquisitions and divestitures:
Restricted cash and investments (increase) decrease	(48,526)	42,123
Premiums, commissions and fees receivable (increase) decrease	(31,324)	2,277
Reinsurance recoverables (increase)	(300,036)	(24,177)
Prepaid reinsurance premiums decrease	(24,324)	(9,191)
Other assets (increase)	1,231	(13,076)
Premiums payable to insurance companies increase	39,787	(37,845)
Premium deposits and credits due customers increase	27,914	12,717
Losses and loss adjustment reserve increase	300,036	24,177
Unearned premiums (decrease)	24,324	9,191
Accounts payable increase	13,858	27,793
Accrued expenses and other liabilities (decrease)	(22,119)	(11,547)
Other liabilities (decrease)	(17,094)	(26,610)
Net cash provided by operating activities	270,609	290,641
Cash flows from investing activities:
Additions to fixed assets	(13,135)	(12,773)
Payments for businesses acquired, net of cash acquired	(113,219)	(109,926)
Proceeds from sales of fixed assets and customer accounts	3,411	4,794
Purchases and proceeds from sales of investments	(24,332)	(16,875)
Proceeds from Sale, Maturity and Collection of Investments	16,716	14,460
Net cash used in investing activities	(130,559)	(120,320)
Cash flows from financing activities:
Payments on acquisition earn-outs	(23,872)	(22,020)
Payments on long-term debt	(34,375)	(38,750)
Income tax benefit from exercise of shares from the stock benefit plans	7,213	2,502
Issuances of common stock for employee stock benefit plans	15,959	15,854
Repurchase Of Stock Benefit Plan Shares For Employees To Fund Tax Withholdings	8,395	2,297
Purchase of treasury stock	(11,250)	(100,000)
Settlement (Prepayment) of accelerated share repurchase program	11,250	0
Cash dividends paid	(51,317)	(46,840)
Net cash (used in) financing activities	(94,787)	(191,551)
Net increase (decrease) in cash and cash equivalents	45,263	(21,230)
Cash and cash equivalents at beginning of period	443,420
Cash and cash equivalents at end of period	$ 488,683	$ 448,818