Consolidated Statements of Financial Position (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Cash and cash equivalents:
Cash and cash due from banks	$ 139,023	$ 130,811	$ 137,586
Interest-bearing deposits with the Federal Reserve Bank	1,271	179,977	69,371
Total cash and cash equivalents	140,294	310,788	206,957
Investment securities:
Available-for-sale, at fair value	615,975	684,570	734,052
Held-to-maturity (fair value - $303,961 at June 30, 2014, $268,271 at December 31, 2013 and $271,397 at June 30, 2013)	308,130	273,905	274,715
Total investment securities	924,105	958,475	1,008,767
Loans held-for-sale, at fair value	6,329	5,219	9,180
Loans	4,898,804	4,647,621	4,335,871
Allowance for loan losses	(77,793)	(79,072)	(82,184)
Net loans	4,821,011	4,568,549	4,253,687
Premises and equipment (net of accumulated depreciation of $104,225 at June 30, 2014, $100,261 at December 31, 2013 and $96,036 at June 30, 2013)	74,291	75,308	73,379
Goodwill	120,164	120,164	120,164
Other intangible assets	12,454	13,424	14,354
Interest receivable and other assets	133,327	132,781	119,723
Total Assets	6,231,975	6,184,708	5,806,211
Deposits:
Noninterest-bearing	1,283,439	1,227,768	1,107,453
Interest-bearing	3,809,474	3,894,617	3,706,732
Total deposits	5,092,913	5,122,385	4,814,185
Interest payable and other liabilities	40,142	38,395	35,460
Short-term borrowings	305,422	327,428	346,995
Total liabilities	5,438,477	5,488,208	5,196,640
Shareholders’ equity:
Preferred stock, no par value: Authorized - 200,000 shares, none issued	0	0	0
Issued and outstanding — 32,760,088 shares at June 30, 2014, 29,789,825 shares at December 31, 2013 and 27,537,554 shares at June 30, 2013	32,760	29,790	27,538
Additional paid-in capital	563,393	488,177	434,479
Retained earnings	215,333	199,053	182,619
Accumulated other comprehensive loss	(17,988)	(20,520)	(35,065)
Total shareholders’ equity	793,498	696,500	609,571
Total Liabilities and Shareholders’ Equity	$ 6,231,975	$ 6,184,708	$ 5,806,211