CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) - $ / shares	6 Months Ended	12 Months Ended
	Apr. 30, 2018	Oct. 31, 2017
Stockholders' Equity:
Excess stock, par value (in dollars per share)	$ 0.01	$ 0.01
Excess stock, shares authorized (in shares)	20,000,000	20,000,000
Excess stock, shares issued (in shares)	0	0
Excess stock, shares outstanding (in shares)	0	0
Common Stock [Member]
Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	30,000,000	30,000,000
Common stock, shares issued (in shares)	9,819,765	9,664,778
Common stock, shares outstanding (in shares)	9,819,765	9,664,778
Class A Common Stock [Member]
Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	29,813,363	29,728,744
Common stock, shares outstanding (in shares)	29,813,363	29,728,744
6.75% Series G Preferred Stock [Member]
Stockholders' Equity:
Preferred stock, dividend rate	6.75%	6.75%
Preferred stock, liquidation preference (in dollars per share)	$ 25	$ 25
Preferred stock, shares issued (in shares)	3,000,000	3,000,000
Preferred Stock, shares outstanding (in shares)	3,000,000	3,000,000
6.25% Series H Preferred Stock [Member]
Stockholders' Equity:
Preferred stock, dividend rate	6.25%	6.25%
Preferred stock, liquidation preference (in dollars per share)	$ 25	$ 25
Preferred stock, shares issued (in shares)	4,600,000	4,600,000
Preferred Stock, shares outstanding (in shares)	4,600,000	4,600,000