Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Interest and Dividend Income
Loans receivable, including loan fees	$ 187,827	$ 168,179	$ 548,395	$ 478,128
Investment securities	8,687	7,546	24,454	21,212
Federal Home Loan Bank stock	301	303	903	1,079
Deposits with banks	1,016	838	4,289	3,667
Total interest and dividend income	197,831	176,866	578,041	504,086
Interest Expense
Time deposits	40,378	22,135	113,992	56,593
Other deposits	6,626	5,474	17,591	14,892
Securities sold under agreements to repurchase	0	124	0	1,446
Advances from Federal Home Loan Bank	1,661	1,430	5,976	3,286
Long-term debt	1,948	2,220	6,087	6,465
Deferred payments from acquisition	93	399	502	946
Short-term borrowings	125	0	198	0
Total interest expense	50,831	31,782	144,346	83,628
Net interest income before reversal for credit losses	147,000	145,084	433,695	420,458
Reversal for credit losses	(2,000)	(1,500)	(2,000)	(4,500)
Net interest income after reversal for credit losses	149,000	146,584	435,695	424,958
Non-Interest Income
Net gains/(losses) from equity securities	364	391	7,764	(4,580)
Securities losses, net	(121)	(14)	(108)	(14)
Letters of credit commissions	1,602	1,459	4,733	4,110
Depository service fees	7,586	6,931	22,791	20,813
Gain from acquisition	0	0	0	340
Other operating income	7,424	4,780	20,097	17,151
Total non-interest income	10,388	7,835	36,103	20,912
Non-Interest Expense
Salaries and employee benefits	31,915	30,514	97,200	91,491
Occupancy expense	5,579	5,186	16,617	15,808
Computer and equipment expense	2,741	2,772	8,453	8,477
Professional services expense	5,952	5,286	17,209	17,055
Data processing service expense	3,246	3,080	9,737	9,450
FDIC and regulatory assessments	2,582	2,555	7,190	6,732
Marketing expense	2,436	1,263	5,556	5,521
Other real estate owned expense/(income)	190	(21)	839	(236)
Amortization of investments in low income housing and alternative energy partnerships	6,997	11,115	26,909	21,989
Amortization of core deposit intangibles	172	190	515	704
Acquisition and integration costs	0	179	0	2,083
Other operating expense	3,770	3,845	15,871	10,949
Total non-interest expense	65,580	65,964	206,096	190,023
Income before income tax expense	93,808	88,455	265,702	255,847
Income tax expense	20,973	18,698	53,944	48,610
Net income	72,835	69,757	211,758	207,237
Other Comprehensive Income, net of tax
Unrealized holding gains/(losses) on securities available-for-sale	1,233	(2,538)	21,216	(16,803)
Unrealized holding (losses)/gains on cash flow hedge derivatives	(793)	1,666	(4,119)	4,595
Less: reclassification adjustments for losses included in net income	(85)	(10)	(76)	(10)
Total other comprehensive gain/(loss), net of tax	525	(862)	17,173	(12,198)
Total other comprehensive income	$ 73,360	$ 68,895	$ 228,931	$ 195,039
Net Income Per Common Share:
Basic (in dollars per share)	$ 0.91	$ 0.86	$ 2.64	$ 2.55
Diluted (in dollars per share)	0.91	0.85	2.64	2.53
Cash dividends (in dollars per share)	$ 0.31	$ 0.24	$ 0.93	$ 0.72
Average Common Shares Outstanding:
Basic (in shares)	79,736,814	81,311,899	80,096,855	81,224,555
Diluted (in shares)	79,993,830	81,855,271	80,330,616	81,770,874
Deposit Account [Member]
Non-Interest Income
Depository service fees	$ 1,119	$ 1,219	$ 3,617	$ 3,905