XML 19 R33.htm IDEA: XBRL DOCUMENT v3.2.0.727
Investments in Marketable Securities (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2015
Jun. 30, 2015
Dec. 31, 2014
Marketable Securities [Abstract]      
Investments in marketable securities $ 261,500,000 $ 261,500,000 $ 172,600,000
Realized gain on available for sale investments $ 7,900,000.0 $ 7,900,000