Consolidated Statements of Changes in Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Class A Common Stock	Class A Common Stock Retained Earnings	Class B Common Stock	Class B Common Stock Retained Earnings
Beginning balance at Dec. 31, 2009	$ 132,730	$ 11,376	$ 120,125	$ (4,301)	$ 3,516		$ 2,014
Net income	13,574		13,574		10,557		3,017
Other comprehensive income, net of tax:
Unrealized holding gains/losses arising during period, net of $415, $3,143 and $2,491 in taxes and $1,851, $1940 and $1,843 in realized net gains for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively	(536)			(536)
Pension liability adjustment, net of $836, $2,439 and $1,223 in taxes for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively	1,259			1,259
Conversion of Class B Common Stock to Class A Common Stock, 3,150, 17,000 and 7,500 shares, for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively					3		(3)
Stock options exercised, 9,950, 2,450 and 12,262 shares, for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively	150	140			10
Tax benefit of stock option exercises	21	21
Cash dividends paid					(1,690)	(1,690)	(483)	(483)
Ending balance at Dec. 31, 2010	145,025	11,537	131,526	(3,578)	3,529		2,011
Net income	16,693		16,693		13,023		3,670
Other comprehensive income, net of tax:
Unrealized holding gains/losses arising during period, net of $415, $3,143 and $2,491 in taxes and $1,851, $1940 and $1,843 in realized net gains for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively	4,726			4,726
Pension liability adjustment, net of $836, $2,439 and $1,223 in taxes for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively	(3,667)			(3,667)
Conversion of Class B Common Stock to Class A Common Stock, 3,150, 17,000 and 7,500 shares, for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively					17		(17)
Stock options exercised, 9,950, 2,450 and 12,262 shares, for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively	52	50			2
Cash dividends paid					(1,701)	(1,701)	(479)	(479)
Ending balance at Dec. 31, 2011	160,649	11,587	146,039	(2,519)	3,548		1,994
Net income	19,039		19,039		14,877		4,162
Other comprehensive income, net of tax:
Unrealized holding gains/losses arising during period, net of $415, $3,143 and $2,491 in taxes and $1,851, $1940 and $1,843 in realized net gains for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively	4,011			4,011
Pension liability adjustment, net of $836, $2,439 and $1,223 in taxes for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively	(1,839)			(1,839)
Conversion of Class B Common Stock to Class A Common Stock, 3,150, 17,000 and 7,500 shares, for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively					8		(8)
Stock options exercised, 9,950, 2,450 and 12,262 shares, for the period ended Dec. 31, 2010, Dec. 31, 2011 and Dec. 31, 2012, respectively	304	292			12
Tax benefit of stock option exercises	12	12
Cash dividends paid					(1,708)	(1,708)	(478)	(478)
Ending balance at Dec. 31, 2012	$ 179,990	$ 11,891	$ 162,892	$ (347)	$ 3,568		$ 1,986