Condensed Consolidated Statements of Operations and Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Interest and Dividend Income
Loans receivable, including loan fees		$ 158,659	$ 129,836	$ 309,949	$ 254,746
Investment securities		7,208	4,719	13,666	9,125
Federal Home Loan Bank stock		380	298	776	710
Deposits with banks		1,273	776	2,829	1,852
Total interest and dividend income		167,520	135,629	327,220	266,433
Interest Expense
Time deposits		18,730	10,769	34,458	21,751
Other deposits		4,832	4,698	9,418	9,144
Securities sold under agreements to repurchase		608	1,065	1,322	2,615
Advances from Federal Home Loan Bank		885	305	1,856	593
Long-term debt		2,163	1,440	4,245	2,864
Deferred payments from acquisition		271		547
Total interest expense		27,489	18,277	51,846	36,967
Net interest income before reversal for credit losses		140,031	117,352	275,374	229,466
Reversal for credit losses				(3,000)	(2,500)
Net interest income after reversal for credit losses		140,031	117,352	278,374	231,966
Non-Interest Income
Net losses from equity securities		(1,124)		(4,971)
Securities gains/(losses), net			3		(463)
Letters of credit commissions		1,376	1,193	2,651	2,316
Depository service fees		7,015	5,999	13,882	12,659
Gain from acquisition				340
Other operating income		6,274	3,612	12,371	8,165
Total non-interest income	[1]	7,767	6,152	13,077	12,870
Non-Interest Expense
Salaries and employee benefits		30,600	26,145	60,977	52,016
Occupancy expense		5,170	4,722	10,622	9,421
Computer and equipment expense		2,611	2,528	5,705	5,252
Professional services expense		5,730	5,343	11,769	9,599
Data processing service expense		3,151	2,396	6,370	4,928
FDIC and regulatory assessments		2,142	2,189	4,177	4,709
Marketing expense		3,400	1,859	4,258	2,730
Other real estate owned (income)/expense		(3)	317	(215)	378
Amortization of investments in low income housing and alternative energy partnerships		5,113	6,224	10,874	11,074
Amortization of core deposit intangibles		280	173	514	345
Acquisition and integration costs		1,735		1,904
Other operating expense		3,159	4,762	7,104	8,092
Total non-interest expense		63,088	56,658	124,059	108,544
Income before income tax expense		84,710	66,846	167,392	136,292
Income tax expense		11,046	15,431	29,912	35,936
Net income		73,664	51,415	137,480	100,356
Other comprehensive income, net of tax
Unrealized holding (losses)/gains on securities available-for-sale		(2,751)	2,774	(14,265)	2,278
Unrealized holding gain/(loss) on cash flow hedge derivatives		736	(550)	2,929	(251)
Less: reclassification adjustments for gains/(losses) included in net income			2		(268)
Total other comprehensive (loss)/gain, net of tax		(2,015)	2,222	(11,336)	2,295
Total other comprehensive income		$ 71,649	$ 53,637	$ 126,144	$ 102,651
Net income per common share:
Basic (in dollars per share)		$ 0.91	$ 0.64	$ 1.69	$ 1.26
Diluted (in dollars per share)		0.90	0.64	1.68	1.25
Cash dividends paid per common share (in dollars per share)		$ 0.24	$ 0.21	$ 0.48	$ 0.42
Weighted-average shares:
Basic (in shares)		81,236,315	79,840,188	81,180,160	79,772,268
Diluted weighted-average number of common shares outstanding (in shares)		81,774,986	80,562,607	81,727,977	80,488,305
Deposit Account [Member]
Non-Interest Income
Depository service fees		$ 1,241	$ 1,344	$ 2,686	$ 2,852

[1] There were no adjustments to the Company's financial statements recorded as a result of the adoption of ASC 606. For comparability, the Company has adjusted prior period amounts to conform to the periods presentation.