Income Taxes (Details) - Income Before Income Tax Provision (USD $)
In Thousands, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2012
Sep. 30, 2012
Jun. 30, 2012
Mar. 31, 2012
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Income Tax [Abstract]                      
Domestic                 $ 64,281 $ 61,983 $ 45,256
International                 14 86 101
Total income before income tax provision $ 10,945 $ 13,260 $ 16,988 $ 23,102 $ 16,080 $ 11,982 $ 21,241 $ 12,766 $ 64,295 $ 62,069 $ 45,357