Subsequent Event (Details) (USD $)	0 Months Ended		3 Months Ended				0 Months Ended
	Mar. 31, 2013	Apr. 23, 2013 Subsequent Event [Member]	Mar. 31, 2013 Subsequent Event [Member]	May 01, 2013 Subsequent Event [Member] Senior Secured Notes [Member]	Apr. 23, 2013 Subsequent Event [Member] Senior Secured Notes [Member]	Apr. 15, 2013 Subsequent Event [Member] Senior Secured Notes [Member]	Apr. 23, 2013 Subsequent Event [Member] LIBOR [Member]	Apr. 23, 2013 Subsequent Event [Member] Base Rate [Member]	Apr. 23, 2013 Subsequent Event [Member] Term Loan [Member]	Apr. 23, 2013 Subsequent Event [Member] Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Period of loan									6 years	5 years
Senior secured credit facility, amount									$ 255,000	$ 20,000
Percentage of term loan amount issued (in hundredths)									99.00%
Rate of interest (in hundredths)		2.00%
Basis spread on variable rate (in hundredths)							4.75%	3.75%
Floor rate of loan (in hundredths)							1.25%	2.25%
Percentage of principal amount tendered (in hundredths)						99.36%
Principal amount of notes tendered						252,000
Payment for each base principal amount					1,066.96
Base principal amount					1,000
Consent payment for each base principal amount					30.00
Face amount to be redeemed					1,614
Redemption price for each base principal amount				1,058.75
Repayments of debt			34,300
Additional transaction expense payments			1,500
Debt issuance cost	$ 154,000