NET INCOME PER COMMON SHARE AND EQUITY PER COMMON SHARE (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Shares used in computing basic and diluted net income per share [Abstract]
Weighted average common shares outstanding during the period for Basic computation (in shares)	8,884,000	8,761,000	8,865,000	8,743,000
Dilutive effect of employee stock options (in shares)	44,000	68,000	49,000	71,000
Weighted average common shares outstanding during the period for Diluted computation (in shares)	8,928,000	8,829,000	8,914,000	8,814,000
Common stock excluded from calculations of diluted net income per share (in shares)			67,500
Class of Stock [Line Items]
Equity per common share (in dollars per share)	$ 13.92		$ 13.92		$ 13.89
Class A Stock [Member]
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	15,000,000		15,000,000
Common stock, shares outstanding (in shares)	8,010,191	7,900,190	8,010,191	7,900,190
Common stock, par value (in dollars per share)	$ 1.00		$ 1.00
Common stock, shares issued during period (in shares)	27,874	41,163	61,622	71,354
Class B Stock [Member]
Class of Stock [Line Items]
Common stock, shares authorized (in shares)	1,040,000		1,040,000
Common stock, shares outstanding (in shares)	881,452	881,452	881,452	881,452
Common stock, par value (in dollars per share)	$ 1.00		$ 1.00
Common stock, shares issued during period (in shares)			881,452	881,452