CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities :
Net income	$ 48,983	$ 58,901
Noncash items:
Amortization of investment premiums	59,063	58,135
Amortization of equity-based awards	1,189	1,066
Other depreciation and amortization	66	66
Change in measureable hedge ineffectiveness related to interest rate swap agreements designated as cash flow hedges	546	26
Net change in receivables, other assets, accounts payable and accrued expenses	(781)	7,497
Net cash provided by operating activities	109,066	125,691
Investing activities:
Purchases of residential mortgage investments	(1,512,737)	(1,936,354)
Interest receivable acquired with the purchase of residential mortgage investments	(1,977)	(3,027)
Principal collections on residential mortgage investments, including changes in mortgage securities principal remittance receivable	1,706,266	1,603,206
Redemption of Federal Home Loan Bank stock	30,000	0
Net cash provided by (used in) investing activities	221,552	(336,175)
Financing activities:
Proceeds from repurchase arrangements and similar borrowings	60,553,581	58,392,825
Principal payments on repurchase arrangements and similar borrowings	(58,584,344)	(58,232,051)
Proceeds from other secured borrowings	1,175,000	0
Principal payments on other secured borrowings	(3,300,000)	0
Increase in cash collateral receivable from interest rate swap counterparties	(42,977)	(187)
Proceeds from issuance of preferred shares	1,167	11,531
Other capital stock transactions	(57)	(429)
Dividends paid	(58,002)	(70,131)
Net cash (used in) provided by financing activities	(255,632)	101,558
Net change in cash and cash equivalents	74,986	(108,926)
Cash and cash equivalents at beginning of period	54,185	307,526
Cash and cash equivalents at end of period	$ 129,171	$ 198,600