Consolidated Balance Sheets (Unaudited) (Parentheticals) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Accumulated depreciation (in Dollars)	$ 111,208	$ 106,871
Preferred stock, par value (in Dollars per share)
Preferred stock, shares authorized	15,000	15,000
Preferred stock, shares outstanding	0	0
Common Class A [Member]
Common stock, par value (in Dollars per share)
Common stock, shares authorized	100,000	100,000
Common stock, shares issued	23,546	23,329
Common stock, shares outstanding	23,546	23,329
Common Class B [Member]
Common stock, par value (in Dollars per share)
Common stock, shares authorized	25,000	25,000
Common stock, shares issued	2,562	2,562
Common stock, shares outstanding	2,562	2,562