Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets
Accounts receivable, allowance	$ 659	$ 621
Property and equipment, accumulated depreciation	$ 13,486	$ 11,685
Class A voting [Member]
Shareholders' equity:
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	3,000,000	3,000,000
Common stock, shares outstanding (in shares)	2,623,109	2,623,109
Class B non-voting [Member]
Shareholders' equity:
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares outstanding (in shares)	12,225,348	12,187,009