Business Segments (Details) $ in Thousands	3 Months Ended								6 Months Ended	12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2016 Segment	Dec. 31, 2019 USD ($) Segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments (segment) | Segment									2	2
Effective income tax rate										22.32%	21.26%	36.36%
Interest income	$ 123,995	$ 126,718	$ 111,950	$ 101,075	$ 103,303	$ 110,045	$ 107,639	$ 96,964		$ 463,739	$ 417,951	$ 372,850
Interest	46,402	50,983	47,271	41,771	41,779	46,044	40,317	31,933		186,429	160,074	105,507
Net interest income	77,593	75,735	64,679	59,304	61,524	64,001	67,322	65,031		277,310	257,877	267,343
Provision for loan and lease losses	9,689	4,426	5,346	4,767	1,385	2,924	(784)	2,117		24,227	5,642	6,768
Non-interest income	25,813	23,369	12,036	19,718	19,877	2,084	16,127	20,910		80,938	58,998	78,910
Non-interest expenses	58,740	59,592	59,582	53,984	57,045	57,104	53,750	52,280		231,901	220,179	215,606
Income before income tax expense	34,977	35,086	11,787	20,271	22,971	6,057	30,483	31,544		102,120	91,054	123,879
Income tax expense	7,451	8,020	2,491	4,831	5,109	28	6,820	7,402		22,793	19,359	45,042
Net income	27,526	27,066	9,296	15,440	17,862	6,029	23,663	24,142		79,327	71,695	78,837
Preferred stock dividends	3,615	3,615	3,615	3,615	3,615	3,615	3,615	3,615		14,459	14,459	14,459
Net income available to common shareholders	23,911	$ 23,451	$ 5,681	$ 11,825	14,247	$ 2,414	$ 20,048	$ 20,527		64,868	57,236	64,378
Goodwill and other intangibles	15,195				16,499					15,195	16,499	16,295
Total assets	11,520,717				9,833,425					11,520,717	9,833,425	9,839,555
Total deposits	8,648,936				7,142,236					8,648,936	7,142,236	6,800,142
Total non-deposit Liabilities	1,818,986				1,734,373					$ 1,818,986	$ 1,734,373	$ 2,118,449
Operating Segments | Customers Bank Business Banking
Segment Reporting Information [Line Items]
Effective income tax rate										22.55%	24.56%	37.67%
Interest income										$ 422,094	$ 400,948	$ 359,931
Interest										185,513	159,674	105,438
Net interest income										236,581	241,274	254,493
Provision for loan and lease losses										10,091	2,928	5,638
Non-interest income										35,268	17,499	24,788
Non-interest expenses										153,333	146,946	128,604
Income before income tax expense										108,425	108,899	145,039
Income tax expense										24,215	23,742	53,013
Net income										84,210	85,157	92,026
Preferred stock dividends										14,459	14,459	14,459
Net income available to common shareholders										69,751	70,698	77,567
Goodwill and other intangibles	3,629				3,629					3,629	3,629	3,630
Total assets	10,990,550				9,688,146					10,990,550	9,688,146	9,769,996
Total deposits	8,247,836				6,766,378					8,247,836	6,766,378	6,400,310
Total non-deposit Liabilities	1,789,329				1,719,225					1,789,329	1,719,225	2,106,919
Operating Segments | BankMobile
Segment Reporting Information [Line Items]
Interest income										41,645	17,003	12,919
Interest										916	400	69
Net interest income										40,729	16,603	12,850
Provision for loan and lease losses										14,136	2,714	1,130
Non-interest income										45,670	41,499	54,122
Non-interest expenses										78,568	73,233	87,002
Income before income tax expense										(6,305)	(17,845)	(21,160)
Income tax expense										(1,422)	(4,383)	(7,971)
Net income										(4,883)	(13,462)	(13,189)
Preferred stock dividends										0	0	0
Net income available to common shareholders										(4,883)	(13,462)	(13,189)
Goodwill and other intangibles	11,566				12,870					11,566	12,870	12,665
Total assets	530,167				145,279					530,167	145,279	69,559
Total deposits	401,100				375,858					401,100	375,858	399,832
Total non-deposit Liabilities	$ 29,657				$ 15,148					29,657	15,148	11,530
Segment Reconciling Items
Segment Reporting Information [Line Items]
Interest income										$ 8,800	$ 15,700	$ 12,900