Subsequent Events (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands									12 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 03, 2021
Subsequent Event [Line Items]
Net proceeds									$ 285,352	$ 268,259	$ 0
Series A Preferred Stock
Subsequent Event [Line Items]
Dividend paid to common stockholders (in dollars per share)	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45
Series B Preferred Stock
Subsequent Event [Line Items]
Dividend paid to common stockholders (in dollars per share)	$ 1.63	$ 1.63	$ 1.63	$ 1.63	$ 1.63	$ 1.63	$ 1.63	$ 1.63
Subsequent Event
Subsequent Event [Line Items]
Cash dividend payable per common share												$ 0.50
Subsequent Event | Series A Preferred Stock
Subsequent Event [Line Items]
Cash dividend payable per common share												0.45
Subsequent Event | Series B Preferred Stock
Subsequent Event [Line Items]
Cash dividend payable per common share												$ 1.63