Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash Flows From Operating Activities
Net income	$ 84,731	$ 74,417
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	10,865	9,023
Amortization of other intangible assets	8,930	6,359
Net premium amortization on investment securities	14,023	10,872
Amortization of FDIC indemnification asset	9,091	36,916
Stock compensation expense	3,517	2,698
Provision for loan losses	2,439	2,228
Net securities gains	(4,056)	(4,961)
Impairment on available-for-sale securities		100
Recognition of deferred gain on sale leaseback transactions	(4,409)	(4,571)
Net gain on branch divestitures	(15,355)
Net gains on sales of other assets	(5,021)	(1,935)
Increase in cash surrender value of company-owned life insurance	(5,438)	(4,939)
Residential real estate loans originated for sale	(278,850)	(106,596)
Proceeds from sale of residential real estate loans	283,971	105,257
Increase in interest receivable	(3,910)	(1,770)
Decrease in other real estate owned	3,331	5,754
(Increase) decrease in other assets	(35,009)	4,384
Increase (decrease) in accrued expenses and other liabilities	(1,416)	1,636
Total adjustments	(17,297)	60,455
Net cash flows provided by operating activities	67,434	134,872
Cash Flows From Investing Activities
Net cash and cash equivalents of acquired banks	(37,098)	7,198
Payments related to branch divestitures	(333,095)
Purchases of investment securities available-for-sale	(716,510)	(289,757)
Purchases of investment securities held-to-maturity	(44,479)	(103,299)
Purchases of Federal Home Loan Bank/Federal Reserve Bank stock	(21,872)	(1,935)
Proceeds from maturities, prepayments and calls of investment securities available-for-sale	601,586	316,532
Proceeds from sales of investment securities available-for-sale	296,841	155,876
Proceeds from maturities, prepayments and calls of investment securities held-to-maturity	32,049	13,762
Proceeds from sales of investment securities held-to-maturity	855
Proceeds from sales of Federal Home Loan Bank/Federal Reserve Bank stock	8,711
Reimbursements under FDIC loss share agreements	3,555	24,814
Net principal collected from (loans made to) loan customers	(185,891)	(157,764)
Proceeds from sale of premises and equipment and other assets	7,709	118
Purchases of premises and equipment and other assets	(14,259)	(15,130)
Net cash flows used in investing activities	(401,898)	(49,585)
Cash Flows From Financing Activities
Deposits	309,793	(295,804)
Short-term borrowings	(88,907)	3,612
Payments for maturities on other borrowings	(227,503)	(193,600)
Proceeds from issuance of other borrowings	400,000	475,000
Cash dividends paid on common stock	(41,817)	(35,266)
Common stock repurchased	(84,245)	(15,284)
Proceeds from exercise of stock options, including tax benefit	298	547
Common stock issued	292	237
Net cash flows provided by (used in) financing activities	267,911	(60,558)
Net increase (decrease) in cash and cash equivalents	(66,553)	24,729
Cash and cash equivalents at beginning of period	239,963	206,723
Cash and cash equivalents at end of period	173,410	231,452
Supplemental cash flow information:
Total interest paid	25,470	15,425
Total taxes paid (net of refunds)	$ 8,784	$ 14,405