Consolidated Statements of Cash Flow $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 70,674	$ 66,170	$ 63,887
Adjustments to reconcile to net cash provided by operating activities:
Provision for loan losses	11,519	7,675	3,072
Depreciation and amortization	12,383	11,901	11,349
Net amortization of securities premiums and discounts	128	1,020	910
Realized securities losses (gains)	59	(9,269)	(1,641)
Gain on sales of loans	(2,825)	(1,968)	(1,813)
Cash receipts from the sale of loans originated for sale	189,620	171,723	152,440
Cash disbursements for loans originated for sale	(182,425)	(174,047)	(153,592)
Deferred income tax benefit	(2,048)	(1,903)	(3,683)
Gain on other assets	(1,252)	(65)	(760)
Increase in interest receivable	(1,497)	(991)	(309)
Increase/(decrease) in interest payable	69	(105)	(333)
Amortization of stock-based compensation arrangements	1,636	1,717	1,676
Other, net	(5,500)	6,301	5,719
Net cash provided by operating activities	90,541	78,159	76,922
INVESTING ACTIVITIES
Net cash and due from banks (paid for) received from acquisitions		(4,007)	174,283
Net (increase)/decrease in federal funds sold	(700)	13,256	4,619
Purchases of held for investment securities	(838)	(1,771)	(708)
Purchases of available for sale securities	(224,655)	(91,136)	(224,217)
Proceeds from maturities, calls and paydowns of held for investment securities	5,260	2,103	4,101
Proceeds from maturities, calls and paydowns of available for sale securities	300,345	55,689	225,394
Proceeds from sales of available for sale securities	481	10,850	4,855
Net change in loans	(176,594)	(243,976)	(366,064)
Purchases of premises, equipment and computer software	(10,835)	(11,263)	(11,490)
Proceeds from the sale of other real estate owned and other assets	9,519	4,957	5,851
Net cash used in investing activities	(98,017)	(265,298)	(183,376)
FINANCING ACTIVITIES
Net change in deposits	274,699	(106,422)	183,371
Net change in short-term borrowings		(3,482)	(608)
Paydown of long-term borrowings			(6,938)
Issuance of common stock, net	13,354	4,428	6,532
Common stock acquired	(5,523)	(1,654)
Cash dividends paid	(22,770)	(21,449)	(19,543)
Net cash provided by (used in) financing activities	259,760	(128,579)	162,814
Net increase/(decrease) in cash, due from banks and interest-bearing deposits	252,284	(315,718)	56,360
Cash, due from banks and interest-bearing deposits at the beginning of the period	1,598,177	1,913,895	1,857,535
Cash, due from banks and interest-bearing deposits at the end of the period	1,850,461	1,598,177	1,913,895
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest	14,673	12,255	13,135
Cash paid during the period for income taxes	32,700	33,531	26,178
Noncash investing and financing activities:
Unpaid common stock dividends declared	$ 5,969	$ 5,615	$ 5,265