Preferred Stock - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Class of Stock [Line Items]
Net proceeds	$ 48,900				$ 48,490
Paid compensation and offering expenses (less than for ATM Agreement)	$ 500
Cost of repurchased of stock				$ 109
Dividends paid		$ 2,029	$ 2,028	4,056	$ 4,055
LIBOR
Class of Stock [Line Items]
Preferred stock dividend accrual rate	8.75%
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)	2,000,000
Preferred stock, price per share (in dollars per share)	$ 25.25
Preferred stock, price per share, net of underwriting discounts and commissions (in dollars per share)	$ 24.45
Repurchased shares (in shares)		4,500
Repurchased stock per share (in dollars per share)		$ 24.70
Cost of repurchased of stock		$ 100
Dividends paid		2,000		4,000
Dividend accrual		$ 2,000		$ 2,000
ATM Agreement | Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, shares issued (in shares)						2,917
Net proceeds						$ 100
Paid compensation and offering expenses (less than for ATM Agreement)						$ 100