CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Operating activities:
Net income	$ 89,514	$ 128,542
Noncash items:
Amortization of investment premiums	101,061	67,346
Depreciation and other amortization	122	142
Amortization of equity-based awards	1,640	1,661
Change in measureable hedge ineffectiveness related to interest rate swap agreements designated as cash flow hedges	(148)	(464)
Gain on sales of real estate held for sale	0	(273)
Net change in receivables, other assets, accounts payable and accrued expenses	1,924	(3,350)
Net cash provided by operating activities	194,113	193,604
Investing activities:
Purchases of residential mortgage investments	(2,876,264)	(3,936,151)
Interest receivable acquired with the purchase of residential mortgage investments	(4,824)	(6,390)
Proceeds from sales of real estate held for sale	0	2,010
Principal collections on residential mortgage investments, including changes in mortgage securities principal remittance receivable	2,790,124	1,918,542
Net cash used in investing activities	(90,964)	(2,021,989)
Financing activities:
Proceeds from repurchase arrangements and similar borrowings	107,161,141	100,706,383
Principal payments on repurchase arrangements and similar borrowings	(107,326,800)	(98,808,335)
Decrease (increase) in cash collateral receivable from interest rate swap counterparties	22,143	(9,232)
Cash paid to redeem Series A & B preferred shares	(207,033)	0
Common share repurchases	(7,292)	0
Proceeds from capital raising activities:
Issuance of preferred shares	164,310	4,479
Issuance of common shares	0	142,035
Other capital stock transactions	(522)	(584)
Dividends paid	(99,439)	(132,337)
Net cash (used in) provided by financing activities	(293,492)	1,902,409
Net change in cash and cash equivalents	(190,343)	74,024
Cash and cash equivalents at beginning of period	425,445	426,717
Cash and cash equivalents at end of period	$ 235,102	$ 500,741