Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Operating activities:
Net income	$ 19,603	$ 16,476
Adjustments to reconcile net income to cash provided by operating activities:
Increase in accrued interest receivable	(1,401)	(3,261)
Decrease in accrued interest payable	(22)	(468)
Provision for loan losses	261	60
Gain on sale of investments, net	(1,391)	(351)
Fair value adjustments, net	157	210
Amortization and depreciation	32,117	13,257
Stock-based compensation expense	490	453
Cash paid for stock appreciation rights	(9)	0
Net change in other assets and other liabilities	(4,400)	(2,053)
Net cash and cash equivalents provided by operating activities	45,405	24,323
Investing activities:
Purchase of investments	(438,376)	(881,854)
Principal payments received on investments	217,358	117,231
(Increase) decrease in principal receivable on investments	(1,607)	4,418
Proceeds from sales of investments	31,158	49,569
Principal payments received on securitized mortgage loans	5,737	13,745
Other investing activities	(1,001)	(534)
Net cash and cash equivalents used in investing activities	(186,731)	(697,425)
Financing activities:
Borrowings under repurchase agreements, net	144,023	592,405
Principal payments on non-recourse collateralized financing	(2,024)	(38,781)
Proceeds from issuance of common stock	5,152	123,733
Payments Related to Tax Withholding for Share-based Compensation	545	0
Dividends paid	(16,960)	(11,307)
Net cash and cash equivalents provided by financing activities	129,646	666,050
Net increase in cash and cash equivalents	(11,680)	(7,052)
Cash and cash equivalents at beginning of period	55,809	48,776
Cash and cash equivalents at end of period	44,129	41,724
Supplemental Disclosure of Cash Activities:
Cash paid for interest	$ 10,381	$ 7,488