CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income	$ 243,318	$ 206,896	$ 217,112
Adjustments to reconcile net income to net cash provided by operating activities:
Amortization	87,421	82,941	67,932
Depreciation	20,890	20,895	17,485
Share-based Compensation	15,513	19,363	22,603
Change in estimated acquisition earn-out payables	3,003	9,938	2,533
Deferred income taxes	22,696	7,369	32,247
Amortization of debt discount	157	46	0
Income tax benefit from exercise of shares from the stock benefit plans	(3,276)	(3,298)	(2,358)
Payments On Acquisition Earn Outs In Excess Of Original Estimated Payables	(11,383)	(2,539)	(2,788)
(Gain)/loss on sales of investments, fixed assets and customer accounts	(107)	42,465	(2,806)
Changes in operating assets and liabilities, net of effect from acquisitions and divestitures:
Restricted cash and investments decrease (increase)	30,016	(9,760)	(85,445)
Premiums, commissions and fees receivable (increase)	(7,163)	(11,160)	(40,729)
Reinsurance recoverables (increase) decrease	(18,940)	12,210	0
Prepaid reinsurance premiums decrease (increase)	10,943	(31,573)	0
Other assets (increase)	(5,318)	(12,564)	(2,583)
Premiums payable to insurance companies decrease	542	8,164	61,624
Premium deposits and credits due customers (decrease) increase	(2,973)	2,323	41,049
Losses and loss adjustment reserve increase (decrease)	18,940	(12,210)	0
Unearned premiums (decrease) increase	(10,943)	31,573	0
Accounts payable increase	34,206	36,949	5,180
Accrued expenses and other liabilities increase	8,204	11,718	70,872
Other liabilities (decrease)	(23,898)	(24,727)	(12,554)
Net cash provided by operating activities	411,848	385,019	389,374
Cash flows from investing activities:
Additions to fixed assets	(18,375)	(24,923)	(16,366)
Payments for businesses acquired, net of cash acquired	(136,000)	(696,486)	(367,712)
Proceeds from sales of fixed assets and customer accounts	10,576	13,631	5,886
Purchases of investments	(22,766)	(17,813)	(18,102)
Proceeds from Sale, Maturity and Collection of Investments	21,928	18,278	15,662
Net cash used in investing activities	(144,637)	(707,313)	(380,632)
Cash flows from financing activities:
Payments on acquisition earn-outs	(25,415)	(9,530)	(15,491)
Proceeds from Issuance of Long-term Debt	0	1,048,425	30,000
Payments on long-term debt	(45,625)	(330,000)	(93)
Income tax benefit from exercise of shares from the stock benefit plans	3,276	3,298	2,358
Issuances of common stock for employee stock benefit plans	15,890	14,808	12,445
Repurchase of stock benefit plan shares for employees to fund tax withholdings	(2,857)	(3,252)	(1,284)
Purchase of treasury stock	(163,750)	(75,025)	0
Prepayment of accelerated share repurchase program	(11,250)	0	0
Cash dividends paid	(64,108)	(59,334)	(53,546)
Net cash (used in) provided by financing activities	(293,839)	589,390	(25,611)
Net (decrease) increase in cash and cash equivalents	(26,628)	267,096	(16,869)
Cash and cash equivalents at beginning of period	470,048	202,952	219,821
Cash and cash equivalents at end of period	443,420	470,048	202,952
Proceeds from Lines of Credit	0	475,000	31,863
Repayments of Lines of Credit	$ 0	$ (475,000)	$ (31,863)