Note 6 - Common Stock and Warrants of ROIC (Details)					3 Months Ended	9 Months Ended
	Aug. 10, 2015 USD ($) shares	Oct. 23, 2014 shares	Sep. 19, 2014 $ / shares shares	Jun. 23, 2011 $ / shares shares	Sep. 30, 2014 USD ($) shares	Sep. 30, 2015 USD ($) $ / shares shares	Sep. 30, 2014 USD ($) shares	Dec. 31, 2014 $ / shares	Jul. 31, 2013 USD ($)
Note 6 - Common Stock and Warrants of ROIC (Details) [Line Items]
Stock Issued During Period, Shares, New Issues | shares	5,520,000
Proceeds from Issuance of Common Stock (in Dollars)	$ 87,300,000					$ 101,293,000	$ 214,907,000
Common Stock, Par or Stated Value Per Share (in Dollars per share) | $ / shares						$ 0.0001		$ 0.0001
Payments of Stock Issuance Costs (in Dollars)						$ 4,286,000	9,462,000
Number of Days Notice				30 days
Proceeds from Warrant Exercises (in Dollars)							$ 56,002,000
Stock Repurchase Program, Authorized Amount (in Dollars)									$ 50,000,000
Stock Repurchased During Period, Shares | shares						0
2014 Sales Agreements ATM Program [Member]
Note 6 - Common Stock and Warrants of ROIC (Details) [Line Items]
Stock Issued During Period, Shares, New Issues | shares						544,567
Proceeds from Issuance of Common Stock (in Dollars)						$ 9,900,000
Number of Sales Agreements Entered Into			4
Common Stock, Par or Stated Value Per Share (in Dollars per share) | $ / shares			$ 0.0001
Common Shares That May be Sold Under a Sales Agreement Aggregate Offering Price, Maximum | shares			100,000,000
Payments of Stock Issuance Costs (in Dollars)						149,000
Minimum Price Company's Common Stock Must Trade Before Warrants Issued in The IPO Can Be Redeemed [Member]
Note 6 - Common Stock and Warrants of ROIC (Details) [Line Items]
Share Price (in Dollars per share) | $ / shares				$ 18.75
Revolving Credit Facility [Member]
Note 6 - Common Stock and Warrants of ROIC (Details) [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity (in Dollars)	$ 500,000,000					$ 500,000,000
Private Placement Warrants [Member]
Note 6 - Common Stock and Warrants of ROIC (Details) [Line Items]
Warrants Purchased By Sponsor During IPO | shares				8,000,000
Warrants, Sales Price Per Warrant (in Dollars per share) | $ / shares				$ 1.00
Public Warrants [Member]
Note 6 - Common Stock and Warrants of ROIC (Details) [Line Items]
Warrants, Repurchase Price Per Warrant (in Dollars per share) | $ / shares				0.01
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per share) | $ / shares				$ 12.00
Class Of Warrant Or Right Number Of Warrants Exercised | shares					1,258,558		4,652,431
Proceeds from Warrant Exercises (in Dollars)					$ 15,100,000		$ 55,800,000
Class of Warrant or Right, Cancelled During Period | shares		64,452
Public and Private Placement Warrants [Member]
Note 6 - Common Stock and Warrants of ROIC (Details) [Line Items]
Common Stock, Capital Shares Reserved for Future Issuance | shares				53,400,000