MANAGEMENT AGREEMENT AND RELATED PARTY TRANSACTIONS (Details) (USD $)	3 Months Ended		3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Manager item	Mar. 31, 2013 Manager Base Management Fees and Manager Share-based Compensation	Mar. 31, 2012 Manager Base Management Fees and Manager Share-based Compensation	Sep. 30, 2007 Manager Base Management Fees and Manager Share-based Compensation	Mar. 31, 2013 Manager Incentive Fees	Mar. 31, 2012 Manager Incentive Fees	Mar. 31, 2013 Manager CLO Management Fees	Mar. 31, 2012 Manager CLO Management Fees	Mar. 31, 2013 Manager Reimbursable General and Administrative Expenses	Mar. 31, 2012 Manager Reimbursable General and Administrative Expenses
Management Agreement and Related Party Transactions
Renewal period			1 year
Votes for termination, minimum (as a percent)			66.70%
Notice period for termination			180 days
Multiplier used to determine termination fee			4
Number of 12 month periods considered for calculation of termination fee			2
Specified period for which average annual incentive fee to be considered			12 months
Expenses recognized by the Company or earned by the manager	$ 17,200,000			$ 9,600,000	$ 7,000,000		$ 17,200,000	$ 9,700,000	$ 800,000	$ 1,100,000	$ 1,700,000	$ 2,000,000
Payable to manager	21,706,000	10,998,000		3,200,000			17,200,000
Expenses recognized for restricted common shares granted				700,000	400,000
Common shares offering						230,400,000
Common share right offering						270,000,000
Common share closing price, minimum (in dollars per share)						$ 20.00
Number of consecutive trading days				5 days
Fees, waived				$ 2,200,000	$ 2,200,000				$ 7,700,000	$ 8,300,000