Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest and Dividend Income
Loans receivable, including loan fees	$ 182,291	$ 158,659	$ 360,568	$ 309,949
Investment securities	8,477	7,208	15,767	13,666
Federal Home Loan Bank stock	298	380	602	776
Deposits with banks	1,383	1,273	3,273	2,829
Total interest and dividend income	192,449	167,520	380,210	327,220
Interest Expense
Time deposits	39,491	18,730	73,614	34,458
Other deposits	5,588	4,832	10,965	9,418
Securities sold under agreements to repurchase	0	608	0	1,322
Advances from Federal Home Loan Bank	1,725	885	4,315	1,856
Long-term debt	2,007	2,163	4,139	4,245
Deferred payments from acquisition	192	271	409	547
Short-term borrowings	67	0	73	0
Total interest expense	49,070	27,489	93,515	51,846
Net interest income before reversal for credit losses	143,379	140,031	286,695	275,374
Reversal for credit losses	0	0	0	(3,000)
Net interest income after reversal for credit losses	143,379	140,031	286,695	278,374
Non-Interest Income
Net gains/(losses) from equity securities	3,237	(1,124)	7,400	(4,971)
Securities gains/(losses), net	13	0	13	0
Letters of credit commissions	1,577	1,376	3,131	2,651
Depository service fees	8,092	7,015	15,204	13,882
Gain from acquisition	0	0	0	340
Other operating income	6,724	6,274	12,673	12,371
Total non-interest income	12,794	7,767	25,715	13,077
Non-Interest Expense
Salaries and employee benefits	33,153	30,600	65,285	60,977
Occupancy expense	5,489	5,170	11,038	10,622
Computer and equipment expense	2,833	2,611	5,712	5,705
Professional services expense	6,000	5,730	11,257	11,769
Data processing service expense	3,081	3,151	6,491	6,370
FDIC and regulatory assessments	2,132	2,142	4,608	4,177
Marketing expense	979	3,400	3,120	4,258
Other real estate owned expense/(income)	369	(3)	649	(215)
Amortization of investments in low income housing and alternative energy partnerships	9,102	5,113	19,912	10,874
Amortization of core deposit intangibles	171	280	343	514
Acquisition and integration costs	0	1,735	0	1,904
Other operating expense	6,237	3,159	12,101	7,104
Total non-interest expense	69,546	63,088	140,516	124,059
Income before income tax expense	86,627	84,710	171,894	167,392
Income tax expense	14,383	11,046	32,971	29,912
Net income	72,244	73,664	138,923	137,480
Other Comprehensive Income, net of tax
Unrealized holding gains/(losses) on securities available-for-sale	11,175	(2,751)	19,974	(14,265)
Unrealized holding (losses)/gains on cash flow hedge derivatives	(2,102)	736	(3,326)	2,929
Total other comprehensive gain/(loss), net of tax	9,073	(2,015)	16,648	(11,336)
Total other comprehensive income	$ 81,317	$ 71,649	$ 155,571	$ 126,144
Net Income Per Common Share:
Basic (in dollars per share)	$ 0.90	$ 0.91	$ 1.73	$ 1.69
Diluted (in dollars per share)	0.90	0.90	1.73	1.68
Cash dividends (in dollars per share)	$ 0.31	$ 0.24	$ 0.62	$ 0.48
Average Common Shares Outstanding:
Basic (in shares)	80,106,329	81,236,315	80,279,859	81,180,160
Diluted (in shares)	80,302,679	81,774,986	80,501,800	81,727,977
Deposit Account [Member]
Non-Interest Income
Depository service fees	$ 1,243	$ 1,241	$ 2,498	$ 2,686