CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash Flows From Operating Activities:
Net income	$ 157,995,000	$ 157,020,000
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sales of MBS and U.S. Treasury securities	(15,597,000)	(18,986,000)
Gain on sales of real estate owned	(2,039,000)	(1,107,000)
Gain on liquidation of residential whole loans	(2,059,000)	0
Other-than-temporary impairment charges	1,032,000	0
Accretion of purchase discounts on MBS and CRT securities and residential whole loans	(46,179,000)	(42,738,000)
Amortization of purchase premiums on MBS and CRT securities	16,002,000	17,417,000
Depreciation and amortization on real estate, fixed assets and other assets	439,000	565,000
Equity-based compensation expense	3,459,000	3,042,000
Unrealized gain on residential whole loans at fair value	(7,209,000)	(14,616,000)
Decrease/(increase) in other assets and other	960,000	(73,632,000)
(Decrease)/increase in other liabilities	(10,660,000)	9,141,000
Net cash provided by operating activities	96,144,000	36,106,000
Cash Flows From Investing Activities:
Principal payments on MBS and CRT securities and other investments	2,461,731,000	1,631,361,000
Proceeds from sales of MBS and U.S. Treasury securities	177,625,000	51,819,000
Purchases of MBS and CRT securities and other investments	(888,736,000)	(924,705,000)
Purchases of residential whole loans and capitalized advances	(9,408,000)	(256,299,000)
Principal payments on residential whole loans	69,615,000	47,104,000
Proceeds from sales of real estate owned	30,459,000	16,133,000
Redemption of Federal Home Loan Bank stock	10,422,000	36,395,000
Additions to leasehold improvements, furniture and fixtures	(333,000)	(247,000)
Net cash provided by investing activities	1,851,375,000	601,561,000
Cash Flows From Financing Activities:
Principal payments on repurchase agreements and other advances	(39,588,099,000)	(40,222,753,000)
Proceeds from borrowings under repurchase agreements and other advances	37,941,405,000	39,872,388,000
Proceeds from issuance of securitized debt	147,847,000	0
Principal payments on securitized debt	(2,652,000)	(22,057,000)
Payments made for securitization related costs	(1,008,000)	0
Payments made for margin calls and settlements on repurchase agreements and interest rate swap agreements (“Swaps”)	(40,478,000)	(181,400,000)
Proceeds from reverse margin calls and settlements on repurchase agreements and Swaps	51,517,000	89,700,000
Proceeds from issuances of common stock	186,250,000	600,000
Dividends paid on preferred stock	(7,500,000)	(7,500,000)
Dividends paid on common stock and dividend equivalents	(149,433,000)	(148,887,000)
Net cash used in financing activities	(1,462,151,000)	(619,909,000)
Net increase in cash and cash equivalents	485,368,000	17,758,000
Cash and cash equivalents at beginning of period	260,112,000	165,007,000
Cash and cash equivalents at end of period	745,480,000	182,765,000
Non-cash Investing and Financing Activities:
Net decrease in securities obtained as collateral/obligation to return securities obtained as collateral	(2,782,000)	(11,675,000)
Transfer from residential whole loans to real estate owned	58,444,000	44,991,000
Dividends and dividend equivalents declared and unpaid	$ 79,559,000	$ 74,584,000