CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities:
Net (loss) income	$ (7,746)	$ 19,420
Noncash items:
Amortization of investment premiums	18,253	25,620
Amortization of equity-based awards	1,109	415
Amortization of unrealized gain on de-designated hedges	(3,020)
Unrealized loss on derivative instruments (net)	26,237
Other depreciation and amortization	27	26
Net change in receivables, other assets, accounts payable and accrued expenses	12,635	1,290
Net cash provided by operating activities	47,495	46,771
Investing activities:
Purchases of residential mortgage investments	(994,371)	(461,381)
Interest receivable acquired with the purchase of residential mortgage investments	(2,190)	(798)
Principal collections on residential mortgage investments, including changes in mortgage securities principal remittance receivable	768,168	812,524
Repayment of lending counterparty investment	5,000
Net cash (used in) provided by investing activities	(223,393)	350,345
Financing activities:
Proceeds from repurchase arrangements and similar borrowings	31,034,056	48,138,234
Principal payments on repurchase arrangements and similar borrowings	(30,790,967)	(48,524,450)
(Decrease) increase in cash collateral receivable from interest rate swap counterparties	(26,394)	5,920
Net (payments on) proceeds from interest rate swap settlements	(56,731)	21,324
Common stock repurchases		(29,062)
Other capital stock transactions	(106)	(72)
Dividends paid	(11,816)	(23,002)
Net cash provided by (used in) financing activities	148,042	(411,108)
Net change in cash and cash equivalents	(27,856)	(13,992)
Cash and cash equivalents at beginning of period	60,289	103,907
Cash and cash equivalents at end of period	$ 32,433	$ 89,915