Fair Value Measurements And Derivative Instruments (Narrative) (Details) - USD ($)				3 Months Ended
	Mar. 01, 2017	Feb. 28, 2017	Mar. 16, 2016	Mar. 31, 2017	Mar. 31, 2016	Feb. 29, 2012
Fair Value Measurements And Derivative Instruments [Line Items]
Transfers between levels				$ 0	$ 0
Interest Rate Instruments [Member]
Fair Value Measurements And Derivative Instruments [Line Items]
Net gain (loss) on interest rate instruments				$ (65,000)	$ 5,730,000
Series C Preferred Stock [Member]
Fair Value Measurements And Derivative Instruments [Line Items]
Preferred stock, annual dividend rate			6.25%
Debt instrument original conversion price, per share						$ 52.00
Warrants [Member]
Fair Value Measurements And Derivative Instruments [Line Items]
Common stock warrants, exercise price						$ 62.40
Common stock warrants, adjusted exercise price			$ 12.48
Adjustment to additional paid in capital, warrant			$ 611,000
Series E Preferred Stock [Member]
Fair Value Measurements And Derivative Instruments [Line Items]
Preferred stock, annual dividend rate		6.25%		6.25%
Redemption Rights [Member] | Series E Preferred Stock [Member]
Fair Value Measurements And Derivative Instruments [Line Items]
Number of shares called by redemption	490,250
Level 3 [Member] | Redemption Rights [Member] | Series E Preferred Stock [Member]
Fair Value Measurements And Derivative Instruments [Line Items]
Assets fair value	$ 150,000	$ 150,000
Minimum [Member] | Series E Preferred Stock [Member]
Fair Value Measurements And Derivative Instruments [Line Items]
Debt instrument conversion amount upon closing of qualified offering	50,000,000
Maximum [Member] | Series E Preferred Stock [Member]
Fair Value Measurements And Derivative Instruments [Line Items]
Debt instrument conversion amount upon closing of qualified offering	$ 75,000,000