Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events (Details)

v3.8.0.1
Subsequent Events (Details) - $ / shares
 3 Months Ended
Apr. 25, 2018
Mar. 31, 2018
Mar. 31, 2017
Subsequent Event [Line Items]      
Dividends declared per share (in dollars per share)   $ 0.750 $ 0.750
Common Stock [Member] | Subsequent Event [Member]      
Subsequent Event [Line Items]      
Dividends declared per share (in dollars per share) $ 0.75    
Series A Cumulative Redeemable Preferred Stock [Member]      
Subsequent Event [Line Items]      
Coupon rate percentage   7.375%  
Series A Cumulative Redeemable Preferred Stock [Member] | Depositary Shares [Member] | Subsequent Event [Member]      
Subsequent Event [Line Items]      
Depositary stock, dividends declared per share (in dollars per share) $ 0.4609375    
Series A Cumulative Redeemable Preferred Stock [Member] | Preferred Stock [Member]      
Subsequent Event [Line Items]      
Coupon rate percentage   7.375%