Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 44,094	$ 19,505	$ 27,268
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	9,892	4,821	3,802
Depreciation of premises and equipment	5,561	4,089	3,757
Net gain on sales of investment securities	(48)	(518)	(1,265)
Net gain on mortgage banking activities	(4,023)	(6,027)	(4,838)
Bank owned life insurance income	(3,988)	(2,931)	(1,295)
Net amortization on investment securities	1,838	1,853	1,284
Amortization, fair market value adjustments and capitalization of mortgage servicing rights	(87)	(521)	(368)
Net accretion of acquisition accounting fair value adjustments	(3,022)	(2,779)	(2,048)
Stock-based compensation	3,166	2,084	1,421
Intangible expenses	2,582	5,528	2,567
Other adjustments to reconcile net income to cash provided by operating activities	(80)	659	(133)
Deferred tax expense	7,483	942	3,816
Originations of loans held for sale	(143,993)	(258,202)	(209,464)
Proceeds from the sale of loans held for sale	152,734	262,948	212,613
Contributions to pension and other postretirement benefit plans	(2,295)	(2,261)	(2,271)
(Increase) decrease in accrued interest receivable and other assets	(1,369)	1,956	3,055
Increase in accrued interest payable and other liabilities	215	2,160	1,442
Net cash provided by operating activities	68,660	33,306	39,343
Cash flows from investing activities:
Net cash paid due to acquisitions	0	(94,835)	(2,967)
Net capital expenditures	(3,961)	(12,644)	(5,890)
Proceeds from maturities, calls and principal repayments of securities held-to-maturity	23,265	21,000	13,000
Proceeds from maturities, calls and principal repayments of securities available-for-sale	94,903	110,927	79,482
Proceeds from sales of securities available-for-sale	7,069	77,290	77,308
Purchases of investment securities held-to-maturity	54,149	5,071	0
Purchases of investment securities available-for-sale	(58,484)	(80,476)	(162,722)
Proceeds from sale of loans transferred to held for sale	0	0	4,000
Proceeds from sale of portfolio loans	0	2,435	0
Net increase in loans and leases	(338,481)	(337,961)	(181,037)
Net (increase) decrease in interest-earning deposits	(19,620)	35,004	(16,954)
Net increase in other investments	(2,335)	(11,773)	(3,718)
Proceeds from sales of other real estate owned	3,996	885	14
Net decrease in federal funds sold	0	0	17,442
Purchases of bank owned life insurance	(7,271)	0	(8,000)
Proceeds from bank owned life insurance	2,961	662	0
Net cash used in investing activities	(352,107)	(294,557)	(190,042)
Cash flows from financing activities:
Net increase in deposits	297,792	125,425	147,572
Net (decrease) increase in short-term borrowings	(90,740)	123,207	(17,763)
Proceeds from issuance of long-term debt	95,000	20,000	0
Repayments of long-term debt	(65,000)	(15,000)	0
Proceeds from issuance of subordinated notes	0	44,515	49,267
Payment of contingent consideration on acquisitions	(5,413)	(2,552)	(2,631)
Proceeds from public offering of common stock	70,501	0	0
Purchases of treasury stock	(3,519)	(8,359)	(13,342)
Stock issued under dividend reinvestment and employee stock purchase plans	2,413	2,472	2,434
Proceeds from exercise of stock options, including excess tax benefits	1,676	4,968	534
Cash dividends paid	(21,299)	(17,024)	(15,011)
Net cash provided by financing activities	281,411	277,652	151,060
Net decrease (increase) in cash and due from banks	(2,036)	16,401	361
Cash and due from banks at beginning of year	48,757	32,356	31,995
Cash and due from banks at end of period	46,721	48,757	32,356
Supplemental disclosures of cash flow information:
Cash paid for interest	21,493	13,982	8,099
Cash paid for income taxes, net of refunds	12,599	8,053	2,142
Non cash transactions:
Transfer of loans to other real estate owned	729	2,347	320
Transfer of loans to loans held for sale	0	0	4,000
Assets acquired through acquisitions	0	1,090,395	425,185
Liabilities assumed through acquisitions	0	911,316	389,795
Contingent consideration recorded as goodwill	$ 0	$ 0	$ 1,525