Consolidated Statement of Changes in Shareholders' Equity (unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
BALANCE-beginning of period at Dec. 31, 2012	$ 207	$ 178,695	$ 7,308	$ 2,001	$ 188,211
BALANCE-beginning of period (in shares) at Dec. 31, 2012	20,748
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			5,985		5,985
Net change in unrealized gains and losses on available‑for‑sale securities, net of taxes of $414 and $60, respectively,and reclassification adjustment				(2,185)	(2,185)
Stock‑based compensation expense		172			172
BALANCE-end of period at Jun. 30, 2013	207	178,867	13,293	(184)	192,183
BALANCE-end of period (in shares) at Jun. 30, 2013	20,748
BALANCE-beginning of period at Dec. 31, 2013	208	179,219	19,918	(127)	199,218
BALANCE-beginning of period (in shares) at Dec. 31, 2013	20,771
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income			8,162		8,162
Net change in unrealized gains and losses on available‑for‑sale securities, net of taxes of $414 and $60, respectively,and reclassification adjustment				1,199	1,199
Issuance of common stock in connection with the exercise of stock options		76			76
Issuance of common stock in connection with the exercise of stock options (in shares)	9
Stock‑based compensation expense		97			97
BALANCE-end of period at Jun. 30, 2014	$ 208	$ 179,392	$ 28,080	$ 1,072	$ 208,752
BALANCE-end of period (in shares) at Jun. 30, 2014	20,780