Parent Company Financial Information (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income:
Interest income	$ 14,159	$ 13,626	$ 13,046	$ 12,116	$ 13,137	$ 12,545	$ 12,809	$ 11,734	$ 52,947	$ 50,225	$ 41,103
Noninterest income	3,194	1,910	6,529	939	257	2,110	(1,093)	5,239	12,572	6,513	(1,076)
Expense:
Interest expense	1,538	1,772	1,764	2,075	2,177	2,314	2,473	2,632	7,149	9,596	12,666
Noninterest expense	8,977	8,031	8,205	6,641	6,616	7,074	6,855	6,359	31,854	26,904	18,948
INCOME BEFORE INCOME TAX									25,765	16,983	6,321
Income tax benefit	2,421	2,126	3,795	1,647	1,519	1,485	303	3,104	9,989	6,411	2,083
NET INCOME	3,811	3,462	5,811	2,692	2,555	2,460	785	4,772	15,776	10,572	4,238
Corporation
Income:
Interest income									4	4	9
Noninterest income									24	6	35
Total income									28	10	44
Expense:
Interest expense									326	310	314
Noninterest expense									1,138	546	488
Total expense									1,464	856	802
INCOME BEFORE INCOME TAX									(1,436)	(846)	(758)
Income tax benefit									(591)	(349)	(312)
Net loss (parent only)									(845)	(497)	(446)
Equity in net earnings of subsidiaries									16,621	11,069	4,684
NET INCOME									$ 15,776	$ 10,572	$ 4,238