Consolidated Statement Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS:
NET INCREASE IN SHAREHOLDERS' EQUITY RESULTING FROM OPERATINGS	$ 42,823	$ 9,786
Reconciliation of the net increase in shareholders' equity resulting from operations to net cash provided by operating activities:
Change in net unrealized (gain) loss on investments and financial derivatives	(46,109)	20,574
Net realized (gain) loss on investments and financial derivatives	23,068	(7,688)
Amortization of premiums and accretion of discounts (net)	(5,150)	(5,250)
Purchase of investments	(1,188,608)	(1,611,306)
Proceeds from disposition of investments	1,257,719	1,611,907
Proceeds from principal payments of investments	63,097	51,973
Proceeds from investments sold short	480,034	939,341
Repurchase of investments sold short	(459,870)	(1,193,783)
Payments made to open financial derivatives	(67,208)	(94,318)
Proceeds received to close financial derivatives	89,373	170,998
Proceeds received to open financial derivatives	35,603	13,087
Payments made to close financial derivatives	(38,363)	(20,734)
Shares issued in connection with incentive fee payment	0	203
Share-based LTIP expense	58	76
(Increase) decrease in assets:
(Increase) decrease in repurchase agreements	(20,998)	3,246
(Increase) decrease in receivable for securities sold	(78,158)	245,578
(Increase) decrease in deposits with dealers held as collateral	4,803	(3)
Increase in interest and principal receivable	(1,002)	(1,409)
Increase in other assets	(626)	(333)
Increase (decrease) in liabilities:
Decrease in due to brokers on margin accounts	(33,350)	(49,904)
Decrease in payable for securities purchased	(44,217)	(66,080)
Increase in accounts payable and accrued expenses	278	348
Increase (decrease) in incentive fee payable	2,312	(1,422)
Increase (decrease) in interest and dividends payable	(224)	16
Increase (decrease) in base management fee payable	101	(76)
Net cash provided by operating activities	15,386	14,827
Cash flows provided by (used in) financing activities:
Offering costs paid	0	(439)
Dividends paid	(18,522)	(28,883)
Proceeds from issuance of securitized debt	1,522	0
Principal payments on securitized debt	(115)	0
Reverse repurchase agreements, net of repayments	(12,888)	24,141
Net cash used in financing activities	(30,003)	(5,181)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	(14,617)	9,646
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD	62,737	35,791
CASH AND CASH EQUIVALENTS, END OF PERIOD	48,120	45,437
Supplemental disclosure of cash flow information:
Interest paid	4,034	3,130
Shares issued in connection with incentive fee payment (non-cash)	0	203
Share-based LTIP awards (non-cash)	58	76
Aggregate TBA trade activity (buys + sells) (non-cash)	$ 8,312,761	$ 11,055,414