Borrowed Funds - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended			0 Months Ended
	Nov. 04, 2002	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Aug. 30, 2009	Jul. 29, 2009
Debt Instrument [Line Items]
Accrued interest		$ 38,100,000	$ 38,800,000
Short-term FHLB advances		2,300,000,000	3,100,000,000
Short-term FHLB advances weighted average interest rate		0.36%	0.38%
Short-term FHLB advances, average balance		2,600,000,000	1,400,000,000
Short-term FHLB advances, average balance, weighted average interest rate		0.37%	0.38%
Short-term FHLB advances, interest expense		9,800,000	5,200,000
Interest expense		392,968,000	399,843,000	486,914,000
Federal funds purchased		260,000,000	445,000,000
Federal funds purchased, average balance		430,100,000	85,800,000
Federal fund purchased Weighted average interest rate		0.25%	0.27%
Federal fund purchased, interest expenses		1,100,000	230,000
Junior Subordinated Debentures Amount Outstanding		358,355,000	358,126,000
Capital security, call option (in years)	5 years
Dividends on the Capital Securities, deferred period in Years		5 years
FHLB - NY
Debt Instrument [Line Items]
Unused line of credit		7,900,000,000	5,400,000,000
Borrowings under line of credit		388,200,000	146,100,000
Line of credit, average balance		245,300,000	106,300,000	29,200,000
Line of credit, weighted average interest rate		0.37%	0.38%	0.38%
Interest expense		895,000	400,000	111,000
Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Acquisition accounting adjustments		12,900,000
Interest expense		255,200,000	252,600,000	311,800,000
Repurchase Agreements
Debt Instrument [Line Items]
Accrued interest		11,800,000	11,900,000
Interest expense		119,300,000	129,600,000	148,300,000
BONUSESSM units | New York Community Capital Trust V (BONUSESSM Units)
Debt Instrument [Line Items]
Public offering of Bifurcated Option Note Unit Securities ("BONUSES units")	5,500,000
Public offering of units, exercise of underwriters' over-allotment option	700,000
Public offering of units, offering price per share	50.00
Public offering of units, net proceeds	267,300,000
Gross proceeds of BONUSES, debt	275,000,000
Difference between the assigned value and the stated liquidation amount of the capital securities is treated as an original issue discount	92,400,000
Original issue discount amortized amount		67,300,000
BONUSESSM units | New York Community Capital Trust V (BONUSESSM Units) | Capital Units
Debt Instrument [Line Items]
Warrant to purchase, number of shares	2.4953
Warrant to purchase, exercise price per share	20.04
Capital security, term (in years)	49 years
Capital security, coupon or distribution rate	6.00%
Capital security, per share liquidation amount	50.00
Gross proceeds of BONUSES	182,600,000
Outstanding BONUSES units						5,498,544
BONUSES units, participated in the exchange offer						1,393,063
BONUSES units, percentage of outstanding units participated in the exchange offer						25.30%
Trust preferred securities were extinguished					48,600,000
Number of shares issued for each BONUSES units						3.4144
Common stock issued as a result of the Offer to Exchange, shares						4,800,000
BONUSESSM units | New York Community Capital Trust V (BONUSESSM Units) | Capital Units | Total
Debt Instrument [Line Items]
Warrant to purchase, total number of shares	13,700,000
BONUSESSM units | New York Community Capital Trust V (BONUSESSM Units) | Warrant
Debt Instrument [Line Items]
Gross proceeds of BONUSES	92,400,000
Junior Subordinated Debt
Debt Instrument [Line Items]
Interest expense		$ 17,200,000	$ 17,300,000	$ 25,000,000
Number of business trusts owned		3