Preferred Stock - Schedule of Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands | May 01, 2017 | Sep. 30, 2017 | Sep. 30, 2017 | Sep. 30, 2016 | Dec. 31, 2016 |
Class of Stock [Line Items] | | | | | |
Proceeds from Issuance or Sale of Equity | $ 540,500 | | | | |
Payments of Stock Issuance Costs | | | $ 16,112 | $ 0 | |
Preferred Stock, Increase (Decrease) In Fair Value | | $ 1,800 | 10,700 | | |
Preferred stock | | 255,646 | 255,646 | | $ 0 |
Change in fair value of preferred stock | | | (10,716) | $ 0 | |
GainLossOnRepurchaseOfPreferredStock | | | 6,000 | | |
Fair Value of Warrants on Date of Issue | | 2,600 | 2,600 | | |
Common Stock [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Class of Warrant or Right, Outstanding | 379,572 | | | | |
Series B Preferred Stock [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred stock | | $ 145,083 | $ 145,083 | | 0 |
Preferred Stock, Shares Issued | 155,000 | | | | |
Preferred Stock, Par or Stated Value Per Share | $ 0.01 | | | | |
Preferred Stock, Redemption Term | 8 years | | | | |
Preferred Stock, Shares Outstanding | | 155,000 | 155,000 | | |
Shares Issued, Price Per Share | $ 1,000 | | | | |
Preferred Stock, Dividend Rate, Percentage | | | 16.73% | | |
Series B Preferred Stock [Member] | Preferred Stock, Redemption, Period Two [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Redemption Price, Percentage | 105.00% | | | | |
Series B Preferred Stock [Member] | Preferred Stock, Redemption, Period Three [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Redemption Price, Percentage | 103.00% | | | | |
Series B Preferred Stock [Member] | Minimum [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Dividend Rate, Component Two, Percentage | 4.75% | | | | |
Series B Preferred Stock [Member] | Maximum [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Dividend Rate, Component Two, Percentage | 12.50% | | | | |
Series B Preferred Stock [Member] | London Interbank Offered Rate (LIBOR) [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Dividend Rate, Component One, Basis Spread On Variable Rate | 3.00% | | | | |
Series C Preferred Stock [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred stock | | $ 68,507 | $ 68,507 | | 0 |
Preferred Stock, Shares Issued | 55,000 | | | | |
Preferred Stock, Par or Stated Value Per Share | $ 0.01 | | | | |
Preferred Stock, Redemption Price, Percentage | 65.00% | | | | |
Preferred Stock, Redemption Term | 8 years | | | | |
Preferred Stock, Shares Outstanding | | 55,000 | 55,000 | | |
Shares Issued, Price Per Share | $ 1,000 | | | | |
Preferred Stock, Dividend Rate, Percentage | | | 16.73% | | |
Series C Preferred Stock [Member] | Minimum [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Dividend Rate, Component Two, Percentage | 4.75% | | | | |
Series C Preferred Stock [Member] | Maximum [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Dividend Rate, Component Two, Percentage | 12.50% | | | | |
Series C Preferred Stock [Member] | London Interbank Offered Rate (LIBOR) [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Dividend Rate, Component One, Basis Spread On Variable Rate | 3.00% | | | | |
Series D Preferred Stock [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred stock | | $ 7,829 | $ 7,829 | | 0 |
Preferred Stock, Shares Issued | 100 | | | | |
Preferred Stock, Par or Stated Value Per Share | $ 0.01 | | | | |
Preferred Stock, Redemption Term | 8 years | | | | |
Preferred Stock, Shares Outstanding | | 100 | 100 | | |
Shares Issued, Price Per Share | $ 1 | | | | |
Preferred Stock, Dividend Rate, Percentage | | | 14.98% | | |
Series F Preferred Stock [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Shares Issued | 240,500 | | | | |
Preferred Stock, Par or Stated Value Per Share | $ 0.01 | | | | |
Preferred Stock, Redemption Term | 6 years | | | | |
Preferred Stock, Shares Outstanding | | 0 | 0 | | |
Shares Issued, Price Per Share | $ 1,000 | | | | |
Series F Preferred Stock [Member] | Preferred Stock, Redemption, Period Four [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Redemption Price, Percentage | 101.00% | | | | |
Series F Preferred Stock [Member] | Preferred Stock, Redemption, Period One [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Redemption Price, Percentage | 106.50% | | | | |
Series F Preferred Stock [Member] | Preferred Stock, Redemption, Period Two [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Redemption Price, Percentage | 103.50% | | | | |
Series F Preferred Stock [Member] | London Interbank Offered Rate (LIBOR) [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Dividend Rate, Component One, Basis Spread On Variable Rate | 6.25% | | | | |
Series E Preferred Stock [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred stock | | $ 34,227 | $ 34,227 | | $ 0 |
Preferred Stock, Shares Issued | 90,000 | | | | |
Preferred Stock, Dividend Rate, Component Two, Percentage | 8.50% | | | | |
Preferred Stock, Redemption Term | 6 years | | | | |
Preferred Stock, Shares Outstanding | | 37,500 | 37,500 | | |
Shares Issued, Price Per Share | $ 1,000 | | | | |
Preferred Stock, Dividend Rate, Percentage | | | 14.98% | | |
Series E Preferred Stock [Member] | Preferred Stock, Redemption, Period One [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Redemption Price, Percentage | 106.50% | | | | |
Series E Preferred Stock [Member] | Preferred Stock, Redemption, Period Two [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Redemption Price, Percentage | 103.50% | | | | |
Series E Preferred Stock [Member] | London Interbank Offered Rate (LIBOR) [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Preferred Stock, Dividend Rate, Component One, Basis Spread On Variable Rate | 5.25% | | | | |
Common Stock [Member] | | | | | |
Class of Stock [Line Items] | | | | | |
Class of Warrant or Right, Terms | 8 years | | | | |
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ 0.01 | | | | |