SUPPLEMENTAL CASH FLOW INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash paid during the year for [Abstract]
Income taxes	$ 14,836	$ 17,662	$ 17,348
Interest	6	84	111
Cash paid during the year for acquisition of assets [Abstract]
Assets acquired	0	0	7,313
Less: liabilities assumed	0	0	(2,652)
Cash paid for acquisitions	0	0	4,661
Non-cash financing activities [Abstract]
Dividends payable	$ 0	$ 5,237	$ 4,311