Long-Term Debt Activity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended			6 Months Ended		0 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Jun. 30, 2012 7.375% Senior Subordinated Notes [Member]	Jun. 03, 2011 7.375% Senior Subordinated Notes [Member]	Jun. 03, 2012 Senior secured credit facility [Member]	Jun. 30, 2012 Senior secured credit facility [Member]	Jun. 30, 2012 Revolving credit line [Member]
Long-Term Debt (Textual) [Abstract]
Aggregate principal amount issued						$ 200,000
Interest rate on notes						7.375%
Notes, maturity date					Jun. 15, 2021
Prepayment of term loan outstanding under its senior secured credit facility							157,235
Debt issuance cost								4,500
Equal quarterly installments due on term loan			2,311		2,311
Remaining principal amount on the extended amount due April 30, 2016					866,602
Term loan debt outstanding									0
Borrowing outstanding under revolving credit line		901,266
Long-Term Debt (Additional Textual) [Abstract]
Prepayment penalties incurred upon early repayment of senior debt		0
Carrying value of long-term debt		1,566,396		1,572,221
Fair value of long-term debt		1,628,826		1,622,286
Write off of unamortization of debt issuance cost		2,183
Reclassification adjustment included in Accumulated comprehensive loss		2,760
Fees on early retirement of debt	$ 2		$ 2