Schedule II - Condensed Financial Information of Registrant (Parent Company Only) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
ASSETS
Cash and cash equivalents	$ 85,145	$ 74,471	$ 60,519	$ 112,270
Investment in subsidiaries	1,702	1,702
Deferred federal income taxes	0	6,738
Other assets	10,985	13,209
Assets	790,468	746,059
LIABILITIES AND STOCKHOLDERS' EQUITY
Revolving credit facility payable	1,473	4,050
Subordinated debt securities	56,702	56,702
Accounts payable and other accrued expenses	23,305	17,954
Liabilities	569,931	529,203
Stockholders' equity:
Common stock, $.18 par value, authorized 33,333,333 shares; issued 20,872,831 shares in 2012 and in 2011	3,757	3,757
Capital in excess of par value	122,475	122,487
Retained earnings	97,964	94,440	105,800	98,500
Accumulated other comprehensive income	7,899	6,446
Treasury stock (1,609,374 shares in 2012 and 2011), at cost	(11,558)	(11,558)
Total stockholders' equity	220,537	215,572	235,278	226,517
Total liabilities and stockholders' equity	790,468	746,059
Parent Company [Member]
ASSETS
Cash and cash equivalents	1,112	3,309	10,983	9,646
Investment in subsidiaries	296,258	288,874
Deferred federal income taxes	2,112	387
Other assets	3,416	3,536
Assets	302,898	296,106
LIABILITIES AND STOCKHOLDERS' EQUITY
Revolving credit facility payable	1,473	4,050
Subordinated debt securities	56,702	56,702
Current federal income tax payable	7,047	3,017
Accounts payable and other accrued expenses	17,139	16,765
Liabilities	82,361	80,534
Stockholders' equity:
Common stock, $.18 par value, authorized 33,333,333 shares; issued 20,872,831 shares in 2012 and in 2011	3,757	3,757
Capital in excess of par value	122,475	122,487
Retained earnings	97,964	94,440
Accumulated other comprehensive income	7,899	6,446
Treasury stock (1,609,374 shares in 2012 and 2011), at cost	(11,558)	(11,558)
Total stockholders' equity	220,537	215,572
Total liabilities and stockholders' equity	$ 302,898	$ 296,106