DEBT (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended
	Sep. 30, 2007 Years	Jun. 30, 2011	Dec. 31, 2010
Revolving Credit Facility
Revolving credit facility	$ 175.0
Period of revolving credit facility (in years)	5
Interest rate terms	Borrowings under the revolving credit facility will bear interest, at the Company's option, at a rate per annum equal to the greater of (a) JPMorgan Chase Bank, National Association's prime lending rate and (b) the federal funds rate plus 1/2 of 1%, plus an applicable margin ranging from 0.25% to 0.75%; or at an adjusted LIBOR for the interest period in effect for such borrowing plus an applicable margin ranging from 1.25% to 1.75%.
Revolving credit facility, commitment fees at the applicable rate, low end of range (as a percent)	0.25%
Revolving credit facility, commitment fees at the applicable rate, high end of range (as a percent)	0.375%
Letters of credit, maximum amount issuable under credit facility		50.0
Letters of credit issued by the company under revolving credit facility		$ 1.6	$ 1.6