CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Operating activities:
Net income	$ 46,137	$ 45,850
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	6,533	6,526
Amortization of intangible assets	1,799	2,242
Net accretion/amortization of premiums and discounts on securities, loans, and borrowings	(1,505)	(1,595)
Stock-based compensation	2,150	2,088
Provision for loan losses	1,214	2,900
Amortization of mortgage servicing rights	206	228
Income from bank-owned life insurance policies	(515)	(511)
Net (gain) loss from sale of loans and other assets	21	(202)
Net change in loans originated for sale	357	148
Change in other assets and liabilities	(2,417)	560
Net cash provided by operating activities	53,980	58,234
Investing activities:
Proceeds from maturities of available-for-sale investment securities	89,631	67,557
Proceeds from maturities of other investment securities	172	14
Purchases of available-for-sale investment securities	(448,747)	(294,417)
Purchases of other securities	(10,312)	(8,105)
Net increase in loans	(31,173)	(43,437)
Cash paid for acquisition, net of cash acquired of $0	0	(924)
Expenditure for intangible asset	(100)	0
Purchases of premises and equipment, net	(5,810)	(3,827)
Net cash used in investing activities	(406,339)	(283,139)
Financing activities:
Net increase in deposits	151,556	75,251
Net change in borrowings, net of payments of $0 and $5	228,200	177,495
Issuance of common stock	5,613	5,599
Purchases of treasury stock	(9,125)	0
Issuances of treasury stock	4,063	0
Cash dividends paid	(24,360)	(22,619)
Tax benefits from share-based payment arrangements	1,063	1,435
Net cash provided by financing activities	357,010	237,161
Change in cash and cash equivalents	4,651	12,256
Cash and cash equivalents at beginning of period	138,396	149,647
Cash and cash equivalents at end of period	143,047	161,903
Supplemental disclosures of cash flow information:
Cash paid for interest	5,321	6,178
Cash paid for income taxes	13,291	11,464
Supplemental disclosures of noncash financing and investing activities:
Dividends declared and unpaid	12,247	11,434
Transfers from loans to other real estate	1,830	1,550
Purchase of intangible asset	$ 241	$ 0