Shareholders’ Equity (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended	6 Months Ended	12 Months Ended
	Apr. 30, 2018	Mar. 31, 2018	Jun. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	May 31, 2018	Oct. 31, 2017
Class of Stock [Line Items]
Preferred shares issued	170,900	1,600,000	2,199,610	2,199,610	0
Preferred shares dividend rate		8.50%		8.50%	8.50%
Preferred shares, par value		$ 0.0001	$ 0.0001	$ 0.0001	$ 0.0001
Preferred shares, liquidation preference		25.00
Preferred shares, redemption price		$ 25.00
Net proceeds from issuance of preferred shares	$ 4.1	$ 38.3
Payments of underwriting discount	$ 0.1
Common Stock [Member]
Class of Stock [Line Items]
Authorized number of shares for issuance in offering program							2,000,000
Issuance of common stock				100,000
Payments of sales commissions				$ 0.1
Proceeds from issuance of stock				$ 2.8
Remaining number of shares for issuance in offering program			1,000,000	1,000,000
Series A Preferred Stock [Member]
Class of Stock [Line Items]
Net proceeds from issuance of preferred shares			$ 10.5
Authorized number of shares for issuance in offering program						2,200,000
Issuance of common stock			428,710
Payments of sales commissions			$ 0.2
Remaining number of shares for issuance in offering program			1,800,000	1,800,000
LIBOR [Member]
Class of Stock [Line Items]
Preferred shares, variable dividend rate		5.82%