Equity and Earnings per Common Share, Common Stock and Preferred Stock ATM Program (Details) - USD ($)		1 Months Ended		3 Months Ended						9 Months Ended
	Jun. 04, 2018	Aug. 31, 2018	Apr. 30, 2018	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Class of Stock Disclosures [Abstract]
Stock issued and sold (in shares)	2,750,000
Issuance of common stock, net of offering costs	$ 53,800,000									$ 4,073,000	$ 60,374,000
Series A Preferred Stock [Member] | Preferred Stock ATM Program [Member]
Class of Stock Disclosures [Abstract]
Preferred stock value authorized			$ 35,000,000
Stock issued and sold (in shares)				0						63,429
Weighted average price (in dollars per share)										$ 25.21
Issuance of common stock, net of offering costs										$ 1,600,000
Stock issuance fee										26,000
Common Stock [Member]
Class of Stock Disclosures [Abstract]
Stock issued and sold (in shares)				0	238,435	6,000	371,041	3,097,113	0
Share Repurchase Program [Abstract]
Share repurchase program, authorized amount				$ 10,000,000						$ 10,000,000
Number of shares repurchased (in shares)				0						0
Common Stock [Member] | Common Stock ATM Program [Member]
Class of Stock Disclosures [Abstract]
Common stock value authorized		$ 50,000,000
Stock issued and sold (in shares)				0						225,646
Weighted average price (in dollars per share)										$ 17.40
Issuance of common stock, net of offering costs										$ 3,900,000
Stock issuance fee										$ 79,000