Stockholders' Equity - Narrative (Details)	1 Months Ended		3 Months Ended				6 Months Ended		12 Months Ended
	Apr. 30, 2020 $ / shares	Mar. 31, 2020 $ / shares	Jun. 30, 2020 $ / shares shares	Mar. 31, 2020 $ / shares	Jun. 30, 2019 USD ($) shares	Mar. 31, 2019 USD ($) shares	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) shares	Dec. 31, 2019 USD ($) $ / shares shares	Apr. 20, 2020	Mar. 31, 2018 USD ($)
Conversion of Stock [Line Items]
Common stock, outstanding (in shares)			89,482,576				89,482,576		89,458,752
Preferred stock, authorized (in shares)			30,000,000				30,000,000
Common stock dividend rate (in dollars per share) | $ / shares		$ 1.60		$ 2.13
Common stock, monthly dividend rate (in dollars per share) | $ / shares		$ 0.40		$ 0.5325
Agent | At-the-Market Program
Conversion of Stock [Line Items]
Number of shares issued (in shares)			0		0	7,759,322	0	0
Gross proceeds from sale of stock | $						$ 152,800,000
Commissions paid | $						1,500,000
Payments of stock offering costs | $						800,000
Aggregate common stock offering price | $						$ 175,000,000.0
Series A Preferred Stock
Conversion of Stock [Line Items]
Payments of stock offering costs | $							$ 75,000
Preferred stock, authorized (in shares)			9,959,650				9,959,650		9,959,650
Preferred stock, dividend rate							7.25%		7.25%
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.01				$ 0.01		$ 0.01
Preferred stock, issued (in shares)			6,799,467				6,799,467		6,799,467
Preferred stock, outstanding (in shares)			6,799,467				6,799,467		6,799,467
Dividend payout (in dollars per share) | $ / shares							$ 0.453125
Preferred stock, liquidation preference (in dollars per share) | $ / shares			$ 25.00				$ 25.00		$ 25
Series A Preferred Stock | Maximum
Conversion of Stock [Line Items]
Periods for dividend payment							30 days
Series A Preferred Stock | Minimum
Conversion of Stock [Line Items]
Periods for dividend payment							10 days
Series A Preferred Stock | Agent | At-the-Market Program
Conversion of Stock [Line Items]
Number of shares issued (in shares)					472,854			540,958
Gross proceeds from sale of stock | $					$ 12,100,000			$ 13,800,000
Commissions paid | $					200,000			200,000
Payments of stock offering costs | $					$ 200,000			$ 300,000
Aggregate preferred stock offering price | $											$ 200,000,000.0
Series B Preferred Stock
Conversion of Stock [Line Items]
Payments of stock offering costs | $							$ 28,000
Preferred stock, authorized (in shares)			11,450,000				11,450,000		11,450,000
Preferred stock, dividend rate							6.875%		6.875%
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.01				$ 0.01		$ 0.01
Preferred stock, issued (in shares)			3,450,000				3,450,000		3,450,000
Preferred stock, outstanding (in shares)			3,450,000				3,450,000		3,450,000
Preferred stock, liquidation preference (in dollars per share) | $ / shares			$ 25				$ 25		$ 25
Preferred stock, quarterly dividend (in dollars per share) | $ / shares							0.429688
Series B Preferred Stock | Public Offering
Conversion of Stock [Line Items]
Preferred stock, liquidation preference (in dollars per share) | $ / shares			$ 25.00				$ 25.00
Series B Preferred Stock | Agent | At-the-Market Program
Conversion of Stock [Line Items]
Aggregate preferred stock offering price | $									$ 200,000,000
Series C Preferred Stock
Conversion of Stock [Line Items]
Preferred stock, authorized (in shares)			100,000				100,000		0
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.01				$ 0.01
Preferred stock, issued (in shares)			0				0		0
Preferred stock, outstanding (in shares)			0				0		0
Percent of outstanding shares acquired	4.90%
Exercise price (in dollars per share) | $ / shares	$ 50.00
Preferred share purchase right basis per share										0.001