Public Offering (Details) - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
	Dec. 09, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Apr. 28, 2014	Apr. 07, 2014
Class of Stock [Line Items]
Share Price (dollars per share)	$ 17.00	$ 21.49			$ 17.54	$ 17.64
Underwriting discount and commission fees (dollars per share)	$ 1.19
Gross proceeds from sale of common stock	$ 109.3
Stock issuance costs	5.9
Proceeds from common stock issuance	$ 103.4
Common Stock
Class of Stock [Line Items]
Issuance of common stock and warrants (shares)	6,400,000	6,426,000	2,678,000	2,488,000
Public Offering | Common Stock
Class of Stock [Line Items]
Issuance of common stock and warrants (shares)	5,600,000
Over-Allotment Option [Member] | Common Stock
Class of Stock [Line Items]
Issuance of common stock and warrants (shares)	838,000
Affiliated Entity [Member] | Common Stock
Class of Stock [Line Items]
Issuance of common stock and warrants (shares)	2,900,000
Affiliated Entity [Member] | Offering Exempt From Underwriter Commission [Member] | Common Stock
Class of Stock [Line Items]
Issuance of common stock and warrants (shares)	2,400,000