Redeemable Preferred Stock (Details)		1 Months Ended	3 Months Ended				12 Months Ended
	Nov. 30, 1998 shares	Dec. 31, 2009 Tranche	Mar. 31, 2017 USD ($) $ / shares shares	Jun. 30, 2016 $ / shares	Mar. 31, 2016 USD ($)	Jun. 30, 2006 USD ($) $ / shares	Dec. 31, 1991 $ / shares shares	Apr. 18, 2017 USD ($)	Dec. 31, 2016 USD ($)	Mar. 31, 2015	Dec. 31, 1990 shares
Senior Redeemable Preferred Stock [Abstract]
Redeemable preferred stock liquidation value (in dollar per share) | $ / shares			$ 1,000
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
Redemption of public preferred stock (in shares)	410,000
Porter [Member] | Subsequent Events [Member]
Class of Stock [Line Items]
Redeemable preferred stock | $								$ 2,112,000
Senior Redeemable Preferred Stock [Member]
Senior Redeemable Preferred Stock [Abstract]
Undeclared unpaid dividends | $			$ 1,600,000
Accrued dividends reported as interest expenses | $			$ 16,000		$ 17,000
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
Preferred stock par value (in dollar per share) | $ / shares			$ 0.01
Preferred stock dividend rate per annum			12.00%				6.00%
Dividends Payable | $			$ 96,800,000						$ 95,900,000
Preferred stock issued and outstanding (in shares)			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
Series A-1 Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock authorized (in shares)			1,250
Preferred stock par value (in dollar per share) | $ / shares			$ 0.01
Preferred stock dividend rate per annum			14.125%
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
Series A-2 Preferred Stock [Member] | Senior Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock issued and outstanding (in shares)			197
Class A Common Stock [Member] | Porter [Member]
Senior Redeemable Preferred Stock [Abstract]
Percentage of redeemable preferred stock held by related party after redemption										39.30%