Fair Value Measurements (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 1991	Apr. 18, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying amount of debt instrument	$ 11,825
Senior Redeemable Preferred Stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Redemption amount of senior redeemable preferred stock			$ 2,100
Carrying amount of senior redeemable preferred stock				$ 2,100
Public Preferred Stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Preferred stock dividend rate per annum	12.00%	6.00%
Public preferred stock par value (in dollar per share)	$ 0.01
Carrying (Reported) Amount, Fair Value Disclosure [Member] | Public Preferred Stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Public preferred stock	$ 129,700			127,700
Estimate of Fair Value, Fair Value Disclosure [Member] | Public Preferred Stock [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Public preferred stock	$ 44,300			$ 31,900