FAIR VALUE MEASUREMENTS Assets Measured at Fair Value Subject to Three-Tier Hierarchy (Details) (Fair Value Measured on a Recurring Basis, USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Fair Value Measurements at Reporting Date Using Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total - net assets	$ 35,122	$ 36,071
Fair Value Measurements at Reporting Date Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents - cash equivalents	13,452	13,127
Fair Value Measurements at Reporting Date Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed Income Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Mutual funds	20,997	21,332
Fair Value Measurements at Reporting Date Using Quoted Prices in Active Markets for Identical Assets (Level 1) | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Mutual funds	673	1,612
Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total - net assets	51,446
Total - net liabilities		(18,745)
Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents - cash equivalents	51,446	10,037
Fair Value Measurements at Reporting Date Using Significant Other Observable Inputs (Level 2) | Interest Rate Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Interest rate swap derivatives - asset		2,725
Interest rate swap derivatives - liability		$ (31,507)