CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) [Abstract]
Interest income	$ 13,363	$ 12,495
Interest expense
Interest on short-term debt	692	317
Interest on long-term debt	125	115
Total interest expense	817	432
Net interest income	12,546	12,063
Other income, net
Investment gain, net	2,808	11,224
Other loss	(4)	(3)
Total other income, net	2,804	11,221
Operating income before other expenses	15,350	23,284
Other expenses
Compensation and benefits	1,960	2,436
Professional services	1,584	123
Business development	17	32
Occupancy and equipment	95	96
Communications	52	46
Other operating expenses	438	295
Total other expenses	4,146	3,028
Income before income taxes	11,204	20,256
Income tax provision	442	471
Net income	10,762	19,785
Basic earnings per share (in dollars per share)	$ 1.37	$ 2.58
Diluted earnings per share (in dollars per share)	$ 1.37	$ 2.58
Dividends declared per share (in dollars per share)	$ 0.875	$ 0.75
Weighted-average shares outstanding (in thousands)
Basic (in shares)	7,865	7,661
Diluted (in shares)	7,873	7,681
Other comprehensive income, net of taxes
Unrealized (losses) gains for the period on available-for-sale securities (net of taxes of $-0-)	(4,903)	2,606
Reclassification adjustment for gains included in net income on available for sale securities (net of taxes of $-0-)	0	(12,850)
Comprehensive income	$ 5,859	$ 9,541