Organization and Basis of Presentation - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2019 Location $ / shares	Dec. 31, 2018 $ / shares	Nov. 23, 1993 $ / shares
Organization and Basis Of Presentation [Line Items]
Common stock, par	$ 0.01	$ 0.01
Description of nine stock splits	($0.93 per share on a split-adjusted basis, reflecting the impact of nine stock splits between 1994 and 2004).
IPO
Organization and Basis Of Presentation [Line Items]
Shares issued, price per share			$ 25.00
Shares issued, price per share, split adjusted basis	$ 0.93
New York Community Bank
Organization and Basis Of Presentation [Line Items]
Number of branches | Location	239