Fair Value Measurements And Derivative Instruments (Narrative) (Details) - USD ($)				3 Months Ended		6 Months Ended
	Mar. 01, 2017	Feb. 28, 2017	Mar. 16, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Feb. 29, 2012
Fair Value Measurements And Derivative Instruments [Line Items]
Transfers between levels				$ 0	$ 0	$ 0	$ 0
Interest Rate Instruments [Member]
Fair Value Measurements And Derivative Instruments [Line Items]
Net gain (loss) on interest rate instruments				$ 202,000	$ (46,000)	$ 137,000	$ 6,458,000
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