Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Parenthetical [Abstract]
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	5,664,000	5,664,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares Outstanding	0	0
Common Stock, Par or Stated Value Per Share	$ 0	$ 0
Common Stock, Shares Authorized	100,000,000	100,000,000
Common Stock, Shares, Issued	38,521,000	36,959,000
Common Stock, Shares, Outstanding	38,521,000	36,959,000