Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Interest income	$ 125,218	$ 111,950	$ 250,561	$ 213,025
Interest expense	33,236	47,271	77,259	89,042
Net interest income	91,982	64,679	173,302	123,983
Provision for credit losses on loans and leases	20,946	5,346	52,732	10,113
Total non-interest income	22,236	12,036	44,167	31,754
Non-interest expense	63,506	59,582	129,965	113,566
Income before income tax expense	29,766	11,787	34,772	32,058
Income tax expense (benefit)	7,048	2,491	8,955	7,323
Net income (loss)	22,718	9,296	25,817	24,735
Preferred stock dividends	3,581	3,615	7,196	7,229
Net income (loss) available to common shareholders	19,137	5,681	18,621	17,506
Goodwill and other intangibles	14,575		14,575		$ 15,195
Total assets	17,903,118		17,903,118		11,520,717
Total deposits	10,965,875		10,965,875		$ 8,648,936
Operating Segments
Segment Reporting Information [Line Items]
Interest income	125,218	111,950	250,561	213,025
Interest expense	33,236	47,271	77,259	89,042
Net interest income	91,982	64,679	173,302	123,983
Provision for credit losses on loans and leases	20,946	5,346	52,732	10,113
Total non-interest income	22,236	12,036	44,167	31,754
Non-interest expense	63,506	59,582	129,965	113,566
Income before income tax expense	29,766	11,787	34,772	32,058
Income tax expense (benefit)	7,048	2,491	8,955	7,323
Net income (loss)	22,718	9,296	25,817	24,735
Preferred stock dividends	3,581	3,615	7,196	7,229
Net income (loss) available to common shareholders	19,137	5,681	18,621	17,506
Goodwill and other intangibles	14,575	15,847	14,575	15,847
Total assets	17,903,118	11,182,427	17,903,118	11,182,427
Total deposits	10,965,875	8,185,777	10,965,875	8,185,777
Total non-deposit liabilities	5,929,396	2,005,245	5,929,396	2,005,245
Operating Segments | Customers Bank Business Banking
Segment Reporting Information [Line Items]
Interest income	112,455	103,014	225,171	195,885
Interest expense	32,856	47,061	76,533	88,666
Net interest income	79,599	55,953	148,638	107,219
Provision for credit losses on loans and leases	19,623	(2,206)	46,921	770
Total non-interest income	11,683	970	22,819	8,547
Non-interest expense	44,270	38,107	88,130	73,491
Income before income tax expense	27,389	21,022	36,406	41,505
Income tax expense (benefit)	6,611	4,629	9,334	9,510
Net income (loss)	20,778	16,393	27,072	31,995
Preferred stock dividends	3,581	3,615	7,196	7,229
Net income (loss) available to common shareholders	17,197	12,778	19,876	24,766
Goodwill and other intangibles	3,629	3,629	3,629	3,629
Total assets	17,316,394	10,555,141	17,316,394	10,555,141
Total deposits	10,303,112	7,729,580	10,303,112	7,729,580
Total non-deposit liabilities	5,895,690	1,970,391	5,895,690	1,970,391
Operating Segments | BankMobile
Segment Reporting Information [Line Items]
Interest income	12,763	8,936	25,390	17,140
Interest expense	380	210	726	376
Net interest income	12,383	8,726	24,664	16,764
Provision for credit losses on loans and leases	1,323	7,552	5,811	9,343
Total non-interest income	10,553	11,066	21,348	23,207
Non-interest expense	19,236	21,475	41,835	40,075
Income before income tax expense	2,377	(9,235)	(1,634)	(9,447)
Income tax expense (benefit)	437	(2,138)	(379)	(2,187)
Net income (loss)	1,940	(7,097)	(1,255)	(7,260)
Preferred stock dividends	0	0	0	0
Net income (loss) available to common shareholders	1,940	(7,097)	(1,255)	(7,260)
Goodwill and other intangibles	10,946	12,218	10,946	12,218
Total assets	586,724	627,286	586,724	627,286
Total deposits	662,763	456,197	662,763	456,197
Total non-deposit liabilities	33,706	34,854	33,706	34,854
Segment Reconciling Items | BankMobile
Segment Reporting Information [Line Items]
Interest income	$ 1,600	$ 2,200	$ 3,100	$ 7,800