Stockholders' Equity - Schedule of Dividends Payable (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
0 Months Ended 12 Months Ended
Dec. 15, 2014
Sep. 16, 2014
Jun. 16, 2014
Mar. 18, 2014
Dec. 17, 2013
Sep. 05, 2013
Jul. 01, 2013
Jun. 17, 2013
Mar. 14, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Equity [Abstract]                        
Dividend Per Share (in dollars per share) $ 0.17000 $ 0.16625 $ 0.16625 $ 0.16625 $ 0.16625 $ 0.135530 $ 0.028530 $ 0.16406 $ 0.16406 $ 0.66875 $ 0.65843  
Total Amount $ 69,927 $ 66,259 $ 66,299 $ 61,628 $ 61,568 $ 50,190 $ 4,622 $ 26,514 $ 26,501 $ 264,113 $ 169,395 $ 28,242