INDEBTEDNESS (Details) - USD ($) $ in Thousands		12 Months Ended
	May. 20, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Long-term debt
Long-term debt		$ 222,000	$ 258,000
Other Long-term Debt, Current		10,000	10,000
Long-term debt		$ 212,000	$ 248,000
Long-term Debt, Weighted Average Interest Rate		1.91%	2.30%
Write-off of deferred financing fees		$ 0	$ 347	$ 0
Debt instrument fees			1,900
Deferred financing fees, net of accumulated amortization		2,300	2,900
Amortization expense related to the deferred financing fees		700	700	$ 600	$ 600
Remaining borrowing capacity		10,600
Eurocurrency
Long-term debt
Basis spread on variable rate (as a percent)	1.00%
Credit agreement
Long-term debt
Maximum borrowing capacity	$ 500,000
Balance of revolving credit facility
Long-term debt
Long-term debt		37,000	63,000
Balance of revolving credit facility | Federal funds rate
Long-term debt
Basis spread on variable rate (as a percent)	0.50%
Term Loan
Long-term debt
Long-term debt		$ 185,000	$ 195,000
Revolving Credit Facility | Credit agreement
Long-term debt
Maximum increase in the borrowing capacity that is available to the company, subject to certain limitations and satisfaction of certain conditions	$ 300,000
Term Loan | Credit agreement
Long-term debt
Maximum increase in the borrowing capacity that is available to the company, subject to certain limitations and satisfaction of certain conditions	200,000
Debt Instrument, Periodic Payment	$ 2,500