Consolidated Balance Sheets (Parenthetical) (USD $)
In Thousands, except Share data, unless otherwise specified
Mar. 31, 2014
Dec. 31, 2013
Property, plant and equipment, accumulated depreciation $ 198,967 $ 179,778
Deferred financing costs, accumulated amortization $ 17,570 $ 16,225
Class A Common Stock [Member]
   
Common stock, par value $ 0.01 $ 0.01
Common stock, shares authorized 500,000,000 500,000,000
Common stock, shares issued 35,703,134 35,530,786
Common stock, shares outstanding 35,703,134 35,530,786
Class B Common Stock [Member]
   
Common stock, par value $ 0.01 $ 0.01
Common stock, shares authorized 20,000,000 20,000,000
Common stock, shares issued 15,555,000 15,555,000
Common stock, shares outstanding 15,555,000 15,555,000