CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities:
Net income	$ 77,420	$ 71,159
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	10,742	9,820
Amortization of intangible assets	4,204	2,642
Net accretion on securities, loans and borrowings	(3,261)	(2,100)
Stock-based compensation	3,392	3,164
Provision for loan losses	5,436	3,120
Amortization of mortgage servicing rights	386	307
Income from bank-owned life insurance policies	(1,124)	(775)
Net gain on sale of loans and other assets	(624)	(48)
Change in other assets and liabilities	3,555	(5,637)
Net cash provided by operating activities	100,126	81,652
Investing activities:
Proceeds from maturities of available-for-sale investment securities	86,885	131,709
Proceeds from maturities of other investment securities	9,050	172
Purchases of available-for-sale investment securities	(40,463)	(494,436)
Purchases of other securities	(4,612)	(9,947)
Net change in loans	(148,384)	(84,064)
Cash paid for acquisition, net of cash acquired of $0 and $0, respectively	(575)	0
Expenditure for intangible asset	0	(100)
Settlement of bank-owned life insurance policies	2,481	0
Purchases of premises and equipment, net	(7,832)	(9,184)
Net cash used in investing activities	(103,450)	(465,850)
Financing activities:
Net increase in deposits	203,945	212,846
Net change in borrowings	(167,400)	220,100
Issuance of common stock	7,556	8,388
Purchases of treasury stock	(716)	(9,125)
Sales of treasury stock	6,925	5,472
Cash dividends paid	(40,883)	(36,584)
Tax benefits from share-based payment arrangements	2,229	1,541
Net cash provided by financing activities	11,656	402,638
Change in cash and cash equivalents	8,332	18,440
Cash and cash equivalents at beginning of period	153,210	138,396
Cash and cash equivalents at end of period	161,542	156,836
Supplemental disclosures of cash flow information:
Cash paid for interest	8,557	8,249
Cash paid for income taxes	23,717	21,334
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	14,220	12,793
Transfers from loans to other real estate	2,137	2,934
Purchase of intangible asset	$ 0	$ 93