Preferred Stock (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Jan. 24, 2018	Aug. 10, 2017
Preferred Stock Disclosure [Line Items]
Preferred Stock, Par Value									$ 250,000
Preferred Stock, Shares Issued	200,000				200,000		200,000		250,000
Preferred Stock, Par or Stated Value Per Share	$ 0.01				$ 0.01		$ 0.01
Issuance of warrants to purchase Common Stock				2,750,000
Class of Warrant or Right, Term				10 years
Class of Warrant or Right, Exercise Price of Warrants or Rights									$ 16.08
Cash purchase price per share of Preferred Stock									970.00
Temporary Equity, Liquidation Preference Per Share									$ 1,000.00
Maximum Preferred Stock Shares Redeemable Within the First Year									50,000
Preferred Stock Shares Redeemed								50,000
Preferred Stock, Percentage Redeemed								20.00%
Payments for Repurchase of Redeemable Preferred Stock			$ 50,500
Redemption Price of Preferred Stock			50,000
Loss on redemption of preferred stock	$ 0	$ 0	7,100		$ 0	$ 7,133
Redemption of Preferred Stock			42,900		$ 0	$ 42,897
Payments Of Accrued Dividends Upon Redemption Of Preferred Stock			$ 500
Carrizo [Member]
Preferred Stock Disclosure [Line Items]
Preferred Stock, Dividend Rate, Percentage				8.875%
Preferred Stock, Par or Stated Value Per Share									$ 0.01