CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
ASSETS
Securities—trading, amortized cost basis	$ 27,203	$ 27,203
Securities—available-for-sale, amortized cost basis	1,690,069	1,529,946
Impact of adopting ASC 326	(102)	0
Securities—held-to-maturity, fair value	$ 450,806	$ 237,805
SHAREHOLDERS’ EQUITY
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	500,000	500,000
Preferred Stock, Shares Outstanding	0	0
Voting Common Stock [Member]
SHAREHOLDERS’ EQUITY
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	50,000,000	50,000,000
Common Stock, Shares, Issued	35,158,568	35,712,384
Common Stock, Shares, Outstanding	35,158,568	35,712,384
Nonvoting Common Stock [Member]
SHAREHOLDERS’ EQUITY
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	5,000,000	5,000,000
Common Stock, Shares, Issued	0	39,192
Common Stock, Shares, Outstanding	0	39,192
Loans [Member] | Recurring [Member]
ASSETS
Loans Held-for-sale, Fair Value Disclosure	$ 152,996	$ 199,397
Loans [Member] | Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
ASSETS
Loans Held-for-sale, Fair Value Disclosure	$ 152,996	$ 199,397