EQUITY AND EARNINGS PER SHARE - Summary of Outstanding Options - Period End (Details) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options (in shares)	12,380,107.000
Options Exercisable (in shares)	7,445,650
Options Granted in 2006 to 2007 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options (in shares)	88,280
Options Granted in 2006 to 2007 [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price (in dollars per share) | $ / shares	$ 29.92
Options Granted in 2006 to 2007 [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price (in dollars per share) | $ / shares	$ 33.80
Options Granted in 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options (in shares)	1,100,497
Options Granted in 2013 [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price (in dollars per share) | $ / shares	$ 10.24
Options Granted in 2013 [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price (in dollars per share) | $ / shares	$ 11.48
Options Granted in 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options (in shares)	258,750
Weighted average exercise price (in dollars per share) | $ / shares	$ 12.20
Options Granted in 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options (in shares)	1,708,708
Options Granted in 2015 [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price (in dollars per share) | $ / shares	$ 15.25
Options Granted in 2015 [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average exercise price (in dollars per share) | $ / shares	$ 15.88
Options Assigned [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options (in shares)	3,156,235
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options (in shares)	4,000
Director [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recipient	Directors
Date of Grant	Various	[1]
Number of options (in shares)	4,000
Options Exercisable (in shares)	4,000
Weighted average exercise price (in dollars per share) | $ / shares	$ 13.58	[2]
Intrinsic value of exercisable options | $	$ 0.0
2003 - 2007 [Member] | Manager [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recipient	Manager	[3]
Date of Grant	2003 - 2007	[1],[3]
Number of options (in shares)	434,000	[3]
Options Exercisable (in shares)	434,000	[3]
Weighted average exercise price (in dollars per share) | $ / shares	$ 31.36	[2],[3]
Intrinsic value of exercisable options | $	$ 0.0	[3]
March 2011 [Member] | Manager [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recipient	Manager	[3]
Date of Grant	2011 - 2012	[1],[3]
Number of options (in shares)	25,000	[3]
Options Exercisable (in shares)	25,000	[3]
Weighted average exercise price (in dollars per share) | $ / shares	$ 7.19	[2],[3]
Intrinsic value of exercisable options | $	$ 0.2	[3]
January 2013 [Member] | Manager [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recipient	Manager	[3]
Date of Grant	2013	[1],[3]
Number of options (in shares)	1,936,068	[3]
Options Exercisable (in shares)	1,936,068	[3]
Weighted average exercise price (in dollars per share) | $ / shares	$ 10.98	[2],[3]
Intrinsic value of exercisable options | $	$ 5.5	[3]
April 2014 [Member] | Manager [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recipient	Manager	[3]
Date of Grant	2014	[1],[3]
Number of options (in shares)	1,437,500	[3]
Options Exercisable (in shares)	1,245,833	[3]
Weighted average exercise price (in dollars per share) | $ / shares	$ 12.20	[2],[3]
Intrinsic value of exercisable options | $	$ 2.0	[3]
April 2015 [Member] | Manager [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recipient	Manager	[3]
Date of Grant	2015	[1],[3]
Number of options (in shares)	8,543,539	[3]
Options Exercisable (in shares)	3,800,749	[3]
Weighted average exercise price (in dollars per share) | $ / shares	$ 15.46	[2],[3]
Intrinsic value of exercisable options | $	$ 0.0	[3]

[1] Options expire on the tenth anniversary from date of grant.

[2] The exercise prices are subject to adjustment in connection with return of capital dividends.

[3] The Manager assigned certain of its options to Fortress’s employees as follows: Date of Grant Range of ExercisePrices Total UnexercisedInception to Date2006-2007 $29.92 to $33.80 88,2802013 $10.24 to $11.48 1,100,4972014 $12.20 258,7502015 $15.25 to $15.88 1,708,708Total 3,156,235