Quarterly report pursuant to Section 13 or 15(d)

Interest Rate Swap (Details)

v2.4.0.8
Interest Rate Swap (Details) (USD $)
In Thousands, unless otherwise specified
1 Months Ended 1 Months Ended 1 Months Ended
Apr. 30, 2014
May 31, 2011
Jun. 30, 2014
Dec. 31, 2013
May 31, 2011
5.75% Senior Notes [Member]
Jun. 30, 2014
5.75% Senior Notes [Member]
Nov. 30, 2012
5.75% Senior Notes [Member]
Apr. 30, 2014
4.75% Percent Senior Notes [Member] [Member]
Jun. 30, 2014
4.75% Percent Senior Notes [Member] [Member]
Derivative [Line Items]                  
Derivative, Notional Amount $ 300,000 $ 250,000              
Debt Instrument, Maturity Date         Jun. 01, 2017     May 15, 2022  
Derivative, Fixed Interest Rate 4.75% 5.75%              
Derivative, Description of Variable Rate Basis three month LIBOR plus 2.27% three month LIBOR plus 3.50%              
Senior notes, at par     725,000 425,000 250,000   175,000 300,000  
Variable rate of swap, percentage     3.73%         2.52%  
Fair value of interest rate swap agreements     $ 9,506 $ 9,576   $ 8,935     $ 571