CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net income	$ 82,873	$ 108,325	$ 140,820
Noncash items:
Amortization of investment premiums	130,084	121,190	101,872
Amortization of equity-based awards	1,440	2,132	2,390
Other depreciation and amortization	124	109	137
Change in measureable hedge ineffectiveness related to interest rate swap agreements designated as cash flow hedges	(47)	(162)	76
Net change in receivables, other assets, accounts payable and accrued expenses	646	12,651	3,517
Net cash provided by operating activities	215,120	244,245	248,812
Investing activities:
Purchases of residential mortgage investments	(3,185,113)	(3,887,051)	(3,307,963)
Interest receivable acquired with the purchase of residential mortgage investments	(4,361)	(5,494)	(5,313)
Principal collections on residential mortgage investments, including changes in mortgage securities principal remittance receivable	3,817,351	3,419,867	2,785,337
Redemptions (purchases) of lending counterparty investments	60,000	(60,002)
Net cash provided by (used in) investing activities	687,877	(532,680)	(527,939)
Financing activities:
Proceeds from repurchase arrangements and similar borrowings	127,822,442	111,006,967	128,594,880
Principal payments on repurchase arrangements and similar borrowings	(125,760,487)	(113,730,416)	(128,270,935)
Proceeds from other secured borrowings	1,175,000	5,425,000
Principal payments on other secured borrowings	(4,050,000)	(2,550,000)
Decrease (increase) in cash collateral receivable from interest rate swap counterparties	20,533	2,946	(27,637)
Proceeds from issuance of preferred shares	1,898	13,266	18,180
Other capital stock transactions	(57)	(429)	(468)
Dividends paid	(109,779)	(132,240)	(140,723)
Net cash (used in) provided by financing activities	(900,450)	35,094	173,297
Net change in cash and cash equivalents	2,547	(253,341)	(105,830)
Cash and cash equivalents at beginning of year	54,185	307,526	413,356
Cash and cash equivalents at end of year	$ 56,732	$ 54,185	$ 307,526