Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 71,932	$ 42,470	$ 23,046
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization of premises and equipment	8,706	6,303	4,786
Allocation of ESOP stock	1,618	919	657
Stock awards	3,038	2,181	1,505
Tax benefit of stock plans	0	0	62
Net excess tax benefit on stock compensation	(722)	(1,823)	0
Amortization of core deposit intangible	3,811	2,039	623
Net accretion of purchase accounting adjustments	(16,733)	(8,216)	(4,505)
Amortization of servicing asset	98	85	157
Net premium amortization in excess of discount accretion on securities	3,893	3,216	1,656
Net amortization of deferred costs and discounts on borrowings	262	74	0
Net amortization (accretion) of deferred fees and discounts on loans	669	509	(274)
Provision for loan losses	3,490	4,445	2,623
Deferred tax (benefit) provision	(4,568)	35,440	5,798
Net loss on sales of other real estate owned	2,359	1,119	138
Write down of fixed assets held for sale to net realizable value	4,024	6,084	0
Net (gain) loss on sales of fixed assets	(26)	150	38
Net unrealized loss on equity securities	199	0	0
Net gain on sales of loans	(668)	(100)	(986)
Net loss on sales of investment securities available for sale		0	12
Proceeds from sales of mortgage loans held-for-sale	2,794	5,282	50,075
Mortgage loans originated for sale	(2,498)	(3,872)	(47,943)
Increase in value of Bank Owned Life Insurance	(5,105)	(3,299)	(2,230)
Net gain on sale of assets held for sale	(1,245)	0	0
Decrease (increase) in interest and dividends receivable	186	(2,265)	(200)
Decrease (increase) in other assets	27,301	(5,375)	18,612
Decrease in other liabilities	(10,264)	(5,235)	(20,226)
Total adjustments	20,619	37,661	10,378
Net cash provided by operating activities	92,551	80,131	33,424
Cash flows from investing activities:
Net decrease (increase) in loans receivable	103,889	(138,271)	106,371
Purchases of loans receivable	(199,580)	(37,337)	(37,561)
Proceeds from sale of under performing loans	10,412	11,186	29,647
Proceeds from sales of debt investment securities available-for-sale		0	41,853
Purchase of debt investment securities available-for-sale	(33,040)	(69,987)	(10,021)
Purchase of debt investment securities held-to-maturity	(6,486)	(125,324)	(6,006)
Purchase of debt mortgage-backed securities held-to-maturity	0	(165,501)	(59,590)
Purchase of equity investments	(191)	0	0
Proceeds from maturities and calls of debt investment securities available-for-sale	19,156	0	18,506
Proceeds from maturities and calls of debt investment securities held-to-maturity	52,543	18,233	53,964
Proceeds from maturities and calls of debt mortgage backed securities held-to-maturity	0	0	6,394
Principal repayments on debt mortgage-backed securities held-to-maturity	119,125	96,383	73,470
Proceeds from Bank Owned Life Insurance	2,708	624	310
Proceeds from the redemption of restricted equity investments	106,807	19,738	32,168
Purchases of restricted equity investments	(127,048)	(20,149)	(23,571)
Net proceeds from sales of other real estate owned	5,438	3,880	3,744
Proceeds from sales of assets held for sale	10,050	0	0
Purchases of premises and equipment	(11,487)	(48,698)	(6,670)
Cash acquired, net of cash paid for branch acquisition	0		16,727
Cash acquired, net of cash consideration paid for acquisitions	(3,743)		31,965
Net cash provided by (used in) investing activities	48,553	(455,223)	271,700
Cash flows from financing activities:
(Decrease) increase in deposits	(143,025)	155,849	131,308
Increase (decrease) in short-term borrowings	126,092	39,733	(175,137)
Proceeds from Federal Home Loan Bank advances	0	10,000	55,161
Repayments of Federal Home Loan Bank advances	(67,155)	(1,922)	(74,153)
Net proceeds from issuance of subordinated notes	0	0	33,898
Repayments of other borrowings	(439)		(10,000)
Increase (decrease) in advances by borrowers for taxes and insurance	2,910	(2,874)	2,286
Exercise of stock options	5,324	3,354	3,989
Payment of employee taxes withheld from stock awards	(3,295)	(1,522)	(555)
Purchase of treasury stock	(10,837)	0	(1,878)
Acquisition of common stock by ESOP	(8,400)	0	0
Dividends paid	(29,564)	(19,286)	(12,616)
Net cash (used in) provided by financing activities	(128,389)	183,332	(47,697)
Net increase (decrease) in cash and due from banks and restricted cash	12,715	(191,760)	257,427
Cash and due from banks and restricted cash at beginning of year	109,613	301,373
Restricted cash at beginning of period	0	0	0
Cash and due from banks and restricted cash at beginning of period	109,613	301,373	43,946
Cash and due from banks and restricted cash at end of year	120,792	109,613	301,373
Restricted cash at end of period	1,536	0	0
Cash and due from banks and restricted cash at end of period	122,328	109,613	301,373
Supplemental disclosure of cash flow information:
Interest	36,447	20,219	13,201
Income taxes	2,317	6,008	10,912
Non-cash investing activities:
Accretion of unrealized loss on securities reclassified to held-to-maturity	2,905	1,145	1,406
Loans charged-off, net	(2,634)	3,907	4,162
Transfer of premises and equipment to assets held-for-sale	11,092	5,729	0
Transfer of loans receivable to other real estate owned	992	3,726	1,833
Non-cash assets acquired:
Securities	254,522	0	305,139
Restricted equity investments	16,967	0	7,932
Loans	1,517,345	0	1,929,986
Premises & equipment	19,892	0	41,067
Other real estate owned	0	0	2,727
Accrued interest receivable	5,621	0	0
Bank Owned Life Insurance	85,238	0	0
Deferred tax asset	57,574	0	21,878
Other assets	6,343	0	97,140
Goodwill and other intangible assets, net	199,838	0	159,649
Total non-cash assets acquired	2,163,340	0	2,565,518
Liabilities assumed:
Deposits	1,616,073	0	2,123,440
Borrowings	127,727	0	128,160
Other liabilities	13,242	0	27,679
Total liabilities assumed	1,757,042	$ 0	2,279,279
Total consideration for acquisition	$ 406,298		$ 286,239