Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	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, 2013	Dec. 31, 2012	Dec. 31, 2011
Current tax expense
Federal													$ 10,322	$ 11,895	$ 9,748
State													336	672	511
Total current tax expense													10,658	12,567	10,259
Deferred tax benefit
Federal													450	(2,800)	(1,934)
State													120	(133)	(134)
Total deferred tax benefit													570	(2,933)	(2,068)
Total income tax expense	2,386	3,091	2,732	3,019	2,265	2,388	2,499	2,482	1,076	2,472	2,441	2,202	11,228	9,634	8,191
Components of income tax expense (benefit) recorded directly to stockholders' equity
Unrealized (loss) gain on securities available for sale													(4,234)	(24)	1,362
Reclassification adjustment for securities losses realized in income													2	0	0
Unrealized gain on derivatives													8	0	0
Compensation expense for tax purposes in excess of amounts recognized for financial reporting purposes													(265)	(83)	(125)
Minimum Pension Liability adjustment													111	2	(111)
Total income tax (benefit) expense recorded directly to stockholders' equity													$ (4,378)	$ (105)	$ 1,126