Borrowed Funds - Junior Subordinated Debentures Outstanding (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2020	Dec. 31, 2019
Subordinated Borrowing [Line Items]
Junior subordinated debentures		$ 360,157	$ 359,866
Capital Securities Amount Outstanding		$ 347,380
New York Community Capital Trust V (BONUSESSM Units)
Subordinated Borrowing [Line Items]
Interest Rate of Capital Securities and Debentures		6.00%
Junior subordinated debentures		$ 146,231
Capital Securities Amount Outstanding		$ 139,880
Date of Original Issue		Nov. 04, 2002
Stated Maturity		Nov. 01, 2051
First Optional Redemption Date	[1]	Nov. 04, 2007
New York Community Capital Trust X
Subordinated Borrowing [Line Items]
Interest Rate of Capital Securities and Debentures		1.85%
Junior subordinated debentures		$ 123,712
Capital Securities Amount Outstanding		$ 120,000
Date of Original Issue		Dec. 14, 2006
Stated Maturity		Dec. 15, 2036
First Optional Redemption Date	[2]	Dec. 15, 2011
PennFed Capital Trust III
Subordinated Borrowing [Line Items]
Interest Rate of Capital Securities and Debentures		3.50%
Junior subordinated debentures		$ 30,928
Capital Securities Amount Outstanding		$ 30,000
Date of Original Issue		Jun. 02, 2003
Stated Maturity		Jun. 15, 2033
First Optional Redemption Date	[2]	Jun. 15, 2008
New York Community Capital Trust XI
Subordinated Borrowing [Line Items]
Interest Rate of Capital Securities and Debentures		1.87%
Junior subordinated debentures		$ 59,286
Capital Securities Amount Outstanding		$ 57,500
Date of Original Issue		Apr. 16, 2007
Stated Maturity		Jun. 30, 2037
First Optional Redemption Date	[2]	Jun. 30, 2012

[1] Callable subject to certain conditions as described in the prospectus filed with the SEC on November 4, 2002.

[2] Callable from this date forward.