LONG-TERM DEBT (Details) (USD $)	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Borrowings [Abstract]
Long-term debt	$ 247,331,000	$ 238,396,000
Less: Current portion	(22,057,000)	(22,057,000)
Total long-term debt	225,274,000	216,339,000
Line of Credit [Member] | LIBOR [Member]
Borrowings [Abstract]
Basis spread on base rate (in hundredths)	1.50%
Line of Credit [Member] | Prime rate [Member]
Borrowings [Abstract]
Basis spread on base rate (in hundredths)	0.50%
Term Loan [Member]
Borrowings [Abstract]
Commitment fee (in hundredths)	0.25%
Incremental higher interest rate after acquisition (in hundredths)	0.25%
Unsecured Subordinated Notes Payable [Member]
Borrowings [Abstract]
Long-term debt	3,154,000	3,870,000
Revolving Credit Facility [Member]
Borrowings [Abstract]
Increase in borrowing capacity		75,000,000
Incremental higher interest rate after acquisition (in hundredths)	0.70%
Available for borrowing under the facility	105,700,000
Expiration date	Jul. 11, 2017
Revolving Credit Facility [Member] | Minimum [Member]
Borrowings [Abstract]
Commitment fee (in hundredths)	0.20%
Revolving Credit Facility [Member] | Maximum [Member]
Borrowings [Abstract]
Commitment fee (in hundredths)	0.40%
Revolving Credit Facility [Member] | LIBOR [Member]
Borrowings [Abstract]
Base rate	LIBOR
Basis spread on base rate (in hundredths)	1.75%
Amount outstanding	241,100,000
Weighted average interest rate (in hundredths)	1.80%
Revolving Credit Facility [Member] | LIBOR [Member] | Minimum [Member]
Borrowings [Abstract]
Basis spread on base rate (in hundredths)	1.25%
Revolving Credit Facility [Member] | LIBOR [Member] | Maximum [Member]
Borrowings [Abstract]
Basis spread on base rate (in hundredths)	2.25%
Revolving Credit Facility [Member] | Prime rate [Member]
Borrowings [Abstract]
Base rate	prime
Amount outstanding	3,100,000
Weighted average interest rate (in hundredths)	3.50%
Revolving Credit Facility [Member] | Prime rate [Member] | Minimum [Member]
Borrowings [Abstract]
Basis spread on base rate (in hundredths)	0.25%
Revolving Credit Facility [Member] | Prime rate [Member] | Maximum [Member]
Borrowings [Abstract]
Basis spread on base rate (in hundredths)	1.25%
Wells Fargo Bank, National Association [Member] | Line of Credit [Member]
Borrowings [Abstract]
Long-term debt	124,489,000	104,526,000
Maximum borrowing capacity	262,500,000
Wells Fargo Bank, National Association [Member] | Term Loan [Member]
Borrowings [Abstract]
Long-term debt	$ 119,688,000	$ 130,000,000