v2.4.0.8
CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $)
In Millions, unless otherwise specified
Jun. 30, 2013
Dec. 31, 2012
Accumulated depreciation on vessels $ 227.4 $ 203.6
Common stock, shares authorized 300 300
Class A [Member]
   
Common stock, shares issued 71.1 71.1
Common stock, shares outstanding 71.1 71.1
Class B [Member]
   
Common stock, shares issued 12.5 12.5
Common stock, shares outstanding 12.5 12.5