Equity (Details)								1 Months Ended		12 Months Ended
	Feb. 17, 2021 $ / shares	Feb. 01, 2021 $ / shares	Oct. 28, 2020 $ / shares	Jul. 29, 2020 $ / shares	May 06, 2020 $ / shares	May 01, 2020 $ / shares	Feb. 13, 2020 $ / shares	Nov. 30, 2020 USD ($) $ / shares shares	Mar. 31, 2020 shares	Dec. 31, 2020 USD ($) Vote $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) shares	Aug. 31, 2020 shares
Common stock
Proceeds from issuance of shares under public offering | $										$ 183,585,000	$ 260,383,000	$ 156,417,000
Repurchase of common stock | $										$ 21,531,000	$ 11,574,000	10,066,000
Noncontrolling Interest
Preferred stock, par value (in dollars per share) | $ / shares										$ 0.01	$ 0.01
Redemption of operating partnership units | $										$ 32,233,000	$ 1,674,000	$ 6,845,000
Preferred Stock
Percentage of dividend paid to common stock and preferred stock shareholders represented ordinary income to our stockholders										100.00%	100.00%	100.00%
Employee compensation and benefits
Deferred Compensation
Share-based compensation expense | $										$ 8,600,000	$ 8,800,000	$ 5,400,000
Selling and administrative expense
Deferred Compensation
Share-based compensation expense | $										500,000	700,000	$ 600,000
Restricted common stock
Deferred Compensation
Total grant date fair value | $										$ 14,400,000	$ 14,800,000
Shares withheld for taxes										175,102
Unrecognized compensation cost | $										$ 6,100,000
Remaining weighted-average vesting period										1 year 7 months 6 days
Restricted stock with grant date fair value (in shares)										1,248,355
Unvested restricted common stock outstanding										1,300,568	1,379,615
Restricted stock vested during the period, grant date fair value | $										$ 8,700,000
Restricted common stock | Chief Executive Officer
Deferred Compensation
Grants during the period (in shares)										45,928	58,738	63,584
Total grant date fair value | $										$ 500,000	$ 700,000	$ 600,000
Restricted common stock | Employees
Deferred Compensation
Total grant date fair value | $										$ 3,400,000	$ 4,200,000	$ 2,300,000
Vesting percentage										33.00%
Number of shares issued in net settlement										314,957	333,884	265,444
Performance-based restricted stock | Chief Executive Officer
Deferred Compensation
Total grant date fair value | $										$ 100,000	$ 1,700,000	$ 800,000
Vesting period (in years)										3 years
Restricted stock vested during period (in shares)										448,980	421,348	445,765
Restricted stock vested during period, net settled (in shares)										215,014	203,492
Restricted stock units eligible to receive										2,325,592	2,325,592	2,325,592
Performance-based restricted stock | Chief Executive Officer | Maximum
Deferred Compensation
Grants during the period (in shares)										275,569	352,427	381,503
8.25% Series A preferred stock
Preferred Stock
Return on the preferred shares issued to third parties by its subsidiary REIT (as a percent)										8.25%	8.25%	8.25%
7.75% Series B preferred stock
Preferred Stock
Return on the preferred shares issued to third parties by its subsidiary REIT (as a percent)										7.75%	7.75%	7.75%
8.50% Series C preferred stock
Preferred Stock
Return on the preferred shares issued to third parties by its subsidiary REIT (as a percent)										8.50%	8.50%	8.50%
Common Stock
Common stock
Number of common stock sold (in shares)										14,790,121	19,837,000	15,152,700
Number of shares purchased								700,000		2,285,178	920,000	870,000
Repurchase of common stock | $										$ 23,000	$ 9,000	$ 9,000
Noncontrolling Interest
Number of shares purchased								700,000		2,285,178	920,000	870,000
Distributions
Cash dividend declared (in dollars per share) | $ / shares	$ 0.33		$ 0.32	$ 0.31	$ 0.30		$ 0.30
Common Stock | Board of Directors
Common stock
Number of common stock sold (in shares)									100.0
Deferred Compensation
Total grant date fair value | $										$ 500,000	$ 700,000	$ 600,000
Number of shares issued in net settlement										52,735	55,244	67,002
Preferred Stock
Common stock
Number of common stock sold (in shares)											0
Preferred Stock | 8.25% Series A preferred stock
Distributions
Cash dividend declared on redeemable preferred stock (in dollars per share) | $ / shares		$ 0.515625	0.515625	0.515625		$ 0.515625	0.515625
Preferred Stock
Return on the preferred shares issued to third parties by its subsidiary REIT (as a percent)		8.25%
Preferred Stock | 7.75% Series B preferred stock
Distributions
Cash dividend declared on redeemable preferred stock (in dollars per share) | $ / shares		$ 0.484375	0.484375	0.484375		0.484375	0.484375
Preferred Stock
Return on the preferred shares issued to third parties by its subsidiary REIT (as a percent)		7.75%
Preferred Stock | 8.50% Series C preferred stock
Distributions
Cash dividend declared on redeemable preferred stock (in dollars per share) | $ / shares		$ 0.53125	$ 0.53125	$ 0.53125		$ 0.53125	$ 0.53125
Preferred Stock
Return on the preferred shares issued to third parties by its subsidiary REIT (as a percent)		8.50%
Total Arbor Realty Trust, Inc. Stockholders' Equity
Common stock
Repurchase of common stock | $										$ 21,531,000	$ 11,574,000	$ 10,066,000
Operating Partnership Units
Common stock
Number of share redeemed										2,736,894
Value of shares redeemed | $										$ 28,400,000
Noncontrolling Interest
Conversion ratio for operating partnership units to common stock shares										1
Redemption of operating partnership units | $										$ 2,768,033
Operating Partnership Units | Special voting preferred shares
Noncontrolling Interest
Preferred stock, par value (in dollars per share) | $ / shares										$ 0.01
Number of vote per share of Special Voting Preferred Shares | Vote										1
OP units outstanding (in shares)										17,560,633
Voting power of outstanding stock (as a percent)										12.50%
5.25% Convertible Notes
Common stock
Shares issued in connection with exchange of convertible debt notes (in shares)										321,412
Interest rate (as a percent)										5.25%		5.25%
5.375% Convertible Notes
Common stock
Shares issued in connection with exchange of convertible debt notes (in shares)										47,086
Interest rate (as a percent)										5.375%		5.375%
6.50% Convertible Notes
Common stock
Interest rate (as a percent)												6.50%
Share repurchase | Common Stock
Common stock
Number of shares purchased										993,106
Repurchase of common stock | $										$ 3,900,000
Noncontrolling Interest
Number of shares purchased										993,106
ACM Acquisition | Performance-based restricted stock | Chief Executive Officer
Deferred Compensation
Grants during the period (in shares)										313,152	246,508	294,985
Total grant date fair value | $										$ 2,900,000	$ 3,000,000.0	$ 3,400,000
Public offering | Common Stock
Common stock
Issued price per share (in dollars per share) | $ / shares								$ 13.30
Number of common stock sold (in shares)								7,000,000
Proceeds from issuance of shares under public offering | $								$ 93,000,000.0
At-The-Market | Common Stock
Common stock
Number of shares available under an "At-The-Market" equity offering with JMP Securities LLC										6,400,000			10,000,000
Issued price per share (in dollars per share) | $ / shares										$ 3.98
Number of common stock sold (in shares)										7,790,121
Proceeds from issuance of shares under public offering | $										$ 90,500,000