CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities:
Net income	$ 22,701	$ 27,353
Noncash items:
Amortization of investment premiums	30,385	26,011
Amortization of equity-based awards	637	745
Other depreciation and amortization	29	32
Change in measureable hedge ineffectiveness related to interest rate swap agreements designated as cash flow hedges	182	393
Net change in receivables, other assets, accounts payable and accrued expenses	(2,453)	(5,740)
Net cash provided by operating activities	51,481	48,794
Investing activities:
Purchases of residential mortgage investments	(1,036,560)	(462,759)
Interest receivable acquired with the purchase of residential mortgage investments	(1,722)	(696)
Principal collections on residential mortgage investments, including changes in mortgage securities principal remittance receivable	933,699	768,187
Redemptions of lending counterparty investments		30,000
Net cash (used in) provided by investing activities	(104,583)	334,732
Financing activities:
Proceeds from repurchase arrangements and similar borrowings	36,205,044	29,191,066
Principal payments on repurchase arrangements and similar borrowings	(36,062,662)	(27,400,760)
Proceeds from other secured borrowings		1,175,000
Principal payments on other secured borrowings		(3,300,000)
Increase in cash collateral receivable from interest rate swap counterparties	(15,265)	(21,844)
Net proceeds from interest rate swap settlements	20,070
Proceeds from issuance of preferred shares	299	200
Other capital stock transactions	(261)	(57)
Dividends paid	(26,217)	(29,262)
Net cash provided by (used in) financing activities	121,008	(385,657)
Net change in cash and cash equivalents	67,906	(2,131)
Cash and cash equivalents at beginning of period	56,732	54,185
Cash and cash equivalents at end of period	$ 124,638	$ 52,054