Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Interest income:
Mortgage securities and similar investments	$ 243,077	$ 199,300	$ 314,100
Other	301	478	495
Interest income	243,378	199,778	314,595
Interest expense:
Repurchase arrangements and similar borrowings	(57,328)	(47,502)	(120,083)
Unsecured borrowings	(8,747)	(8,747)	(8,747)
Other	(5)	(2)
Interest expense	(66,080)	(56,251)	(128,830)
Net interest income (expense)	177,298	143,527	185,765
Other revenue (expense):
Miscellaneous other revenue (expense)	(1,023)	(904)	(40,641)
Incentive compensation expense	(5,697)	(5,055)	(4,769)
Salaries and benefits	(6,701)	(6,097)	(5,655)
Other general and administrative expense	(3,932)	(4,834)	(5,696)
Operating expenses	(17,353)	(16,890)	(56,761)
Income before equity in earnings of unconsolidated affiliates	159,945	126,637	129,004
Equity in earnings of unconsolidated affiliates	259	259	259
Net income	160,204	126,896	129,263
Net income available to common stockholders:
Net income	160,204	126,896	129,263
Less cash dividends paid on preferred shares	(20,369)	(20,233)	(20,239)
Net income (loss) available to common stockholders, basic, total	$ 139,835	$ 106,663	$ 109,024
Net income per common share:
Basic	$ 1.76	$ 1.53	$ 1.67
Diluted	$ 1.75	$ 1.52	$ 1.66