Business Combinations - SB One Bancorp Acquisition (Details) $ in Thousands		3 Months Ended
	Jul. 31, 2020 USD ($) numberOfBankingOffices shares	Mar. 31, 2021 USD ($) branch	Dec. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)
Business Acquisition [Line Items]
Fair value of acquired loans at July 31, 2020	$ 1,766,115
Excess of consideration paid recorded as goodwill	22,400
Fair value premium	8,400
Allowance for credit losses		$ 85,591	$ 101,466	$ 75,143	$ 55,525	$ 55,525
Number of branches acquired | branch		18
Number of branches owned | branch		8
Subordinated debentures		$ 25,173	$ 25,135
SB One Bancorp
Business Acquisition [Line Items]
Business combination assets acquired	$ 2,195,708
Number of banking offices | numberOfBankingOffices	18
Common stock portion, number of SB One Bancorp stock for each share of company common stock converted | shares	1.357
Common stock, total amount of company stock | shares	12,800,000
Total cost of acquisition	$ 180,800
Fair value premium	133
Allowance for credit losses	13,600
Bank-owned life insurance	37,200
Time deposit discount	4,300
Subordinated debentures	27,500
SB One Bancorp | Core Deposits
Business Acquisition [Line Items]
Intangible asset	$ 3,200
Estimated useful life	10 years
SB One Bancorp | Customer Relationships
Business Acquisition [Line Items]
Intangible asset	$ 6,800
Estimated useful life	13 years
SB One Bancorp | Loans
Business Acquisition [Line Items]
Fair value of acquired loans at July 31, 2020	$ 1,770,000
SB One Bancorp | Deposits
Business Acquisition [Line Items]
Fair value of acquired loans at July 31, 2020	$ 1,760,000