CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating activities:
Net income	$ 127,818	$ 78,691
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	11,854	12,026
Amortization of intangible assets	13,780	11,980
Net accretion on securities, loans and borrowings	(7,141)	(4,412)
Stock-based compensation	4,607	3,985
Provision for loan losses	8,342	5,603
Amortization of mortgage servicing rights	340	374
Unrealized gain on equity securities	(722)	0
Loss on debt extinguishment	318	0
Income from bank-owned life insurance policies	(1,177)	(1,170)
Net (gain) loss on sale of loans and other assets	(207)	155
Change in other assets and other liabilities	8,769	31,624
Net cash provided by operating activities	166,581	138,856
Investing activities:
Proceeds from maturities of available-for-sale investment securities	102,549	110,160
Proceeds from maturities of other investment securities	8,292	28,580
Purchases of available-for-sale investment securities	(47,495)	(59,425)
Purchases of other securities	(31)	(12,434)
Net (increase) decrease in loans	(51,170)	120,029
Cash paid for acquisitions, net of cash acquired of $16 and $51,793, respectively	(1,737)	(105,402)
Settlement of bank-owned life insurance policies	0	1,779
Purchases of premises and equipment, net	(8,903)	(7,701)
Net cash provided by investing activities	1,505	75,586
Financing activities:
Net increase in deposits	19,401	81,630
Net decrease in borrowings	(86,523)	(193,602)
Payments on subordinated debt held by unconsolidated subsidiary trusts	(25,207)	0
Issuance of common stock	5,794	3,740
Purchases of treasury stock	(220)	(3,226)
Sales of treasury stock	7,226	7,861
Increase in deferred compensation arrangements	220	3,226
Cash dividends paid	(52,006)	(45,059)
Withholding taxes paid on share-based compensation	(971)	(1,389)
Net cash used in financing activities	(132,286)	(146,819)
Change in cash and cash equivalents	35,800	67,623
Cash and cash equivalents at beginning of period	221,038	173,857
Cash and cash equivalents at end of period	256,838	241,480
Supplemental disclosures of cash flow information:
Cash paid for interest	12,870	10,092
Cash paid for income taxes	20,674	33,187
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	19,634	17,412
Transfers from loans to other real estate	2,426	2,470
Acquisitions:
Common stock issued	0	340,737
Fair value of assets acquired, excluding acquired cash and intangibles	115	1,960,922
Fair value of liabilities assumed	$ 31	$ 1,869,854