Redeemable Preferred Stock (Details)		1 Months Ended	3 Months Ended			6 Months Ended		12 Months Ended
	Nov. 30, 1998 shares	Dec. 31, 2009 Tranche	Jun. 30, 2017 USD ($) $ / shares shares	Jun. 30, 2016 USD ($) $ / shares	Jun. 30, 2006 USD ($) $ / shares	Jun. 30, 2017 USD ($) $ / shares shares	Jun. 30, 2016 USD ($) $ / shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 1991 $ / shares shares	Apr. 18, 2017 USD ($)	Dec. 31, 1990 shares
Class of Stock [Line Items]
Preferred stock par value (in dollar per share) | $ / shares								$ 0.01
12% Cumulative Exchangeable Redeemable Preferred Stock [Abstract]
Number of annual tranches during the period | Tranche		5
Period during which redeemable preferred stock not callable				12 months
Preferred stock dividend rate per annum (in dollars per share) | $ / shares					$ 1.20
Preferred stock, liquidation preference (in dollars per share) | $ / shares				$ 10			$ 10
Redemption of public preferred stock (in shares)	410,000
Senior Redeemable Preferred Stock [Member]
Senior Redeemable Preferred Stock [Abstract]
Redemption amount of senior redeemable preferred stock | $										$ 2,100,000
Undeclared unpaid dividends | $								$ 1,600,000
Accrued dividends reported as interest expenses | $			$ 16,000	$ 17,000		$ 20,000	$ 33,000
Senior Redeemable Preferred Stock [Member] | Toxford [Member]
Senior Redeemable Preferred Stock [Abstract]
Senior redeemable preferred stock maturity date						May 31, 2018
Percentage of redeemable preferred stock held by related party after redemption								76.40%
Public Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock authorized (in shares)			6,000,000			6,000,000
Preferred stock par value (in dollar per share) | $ / shares			$ 0.01			$ 0.01
Preferred stock dividend rate per annum						12.00%			6.00%
Dividends Payable | $				$ 97,800,000			$ 97,800,000	$ 95,900,000
Preferred stock issued and outstanding (in shares)			3,185,586			3,185,586
Preferred stock issued (in shares)											2,858,723
12% Cumulative Exchangeable Redeemable Preferred Stock [Abstract]
Adjusted accrued accretion of public preferred stock | $					$ 1,500,000
Number of shares declared as dividend (in shares)									736,863
Preferred stock dividend rate per annum (in dollars per share) | $ / shares									$ 0.60
Dividends on preferred stock | $			$ 1,000,000			$ 1,900,000
Series A-1 Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock authorized (in shares)								1,250
Preferred stock dividend rate per annum								14.125%
Preferred stock issued and outstanding (in shares)								197
Senior Redeemable Preferred Stock [Abstract]
Redeemable preferred stock liquidation value (in dollar per share) | $ / shares								$ 1,000
Series A-2 Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock authorized (in shares)								1,750
Preferred stock issued and outstanding (in shares)								276
Class A Common Stock [Member] | Porter [Member]
Senior Redeemable Preferred Stock [Abstract]
Percentage of redeemable preferred stock held by related party after redemption			34.90%			34.90%