SUPPLEMENTAL CASH FLOW FINANCIAL INFORMATION (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash paid during the period for:
Interest	$ 25,230	$ 27,362	$ 27,799
Income taxes	34,409	34,468	17,152
Non-cash financing and investing activities:
Issuance of notes in connection with acquisitions	2,650	21,895	6,700
Issuance of restricted stock units	$ 11,698	$ 5,996	$ 12,754