CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common stock amount	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income	Treasury stock
Balance at beginning of period at Dec. 31, 2015	$ 154,152	$ 13,577	$ 21,624	$ 122,260	$ 3,629	$ (6,938)
Comprehensive income:
Net income	8,717			8,717
Other comprehensive loss	4,862				4,862
Total comprehensive income	13,579			8,717	4,862
Cash dividends declared ($0.37 and $0.36 per share for the six months ended June 30, 2017 and 2016, respectively)	(3,219)			(3,219)
Treasury stock purchased (2,861 and 22,425 for the six months ended June 30, 2017 and 2016, respectively)	(481)					(481)
Net issuance (49,029 and 51,636 for the six months ended June 30, 2017 and 2016, respectively) to employee stock plans, including related tax effects	355		92	(86)		349
Stock-based compensation	845		845
Balance at end of period at Jun. 30, 2016	165,231	13,577	22,561	127,672	8,491	(7,070)
Balance at beginning of period at Mar. 31, 2016					7,065
Comprehensive income:
Net income	4,311
Other comprehensive loss	1,426
Total comprehensive income	5,737
Balance at end of period at Jun. 30, 2016	165,231	13,577	22,561	127,672	8,491	(7,070)
Balance at beginning of period at Dec. 31, 2016	156,740	13,577	23,027	130,489	(4,326)	(6,027)
Comprehensive income:
Net income	10,767			10,767
Other comprehensive loss	2,621				2,621
Total comprehensive income	13,388			10,767	2,621
Cash dividends declared ($0.37 and $0.36 per share for the six months ended June 30, 2017 and 2016, respectively)	(5,744)			(5,744)
Treasury stock purchased (2,861 and 22,425 for the six months ended June 30, 2017 and 2016, respectively)	(86)					(86)
Acquisition of Lake Sunapee Bank Group	181,919	8,328	173,591
Net issuance (49,029 and 51,636 for the six months ended June 30, 2017 and 2016, respectively) to employee stock plans, including related tax effects	365		(68)	(40)		473
Three-for-two stock split	(16)	10,952	(10,952)	(16)
Stock-based compensation	556		556
Balance at end of period at Jun. 30, 2017	347,122	32,857	186,154	135,456	(1,705)	(5,640)
Balance at beginning of period at Mar. 31, 2017					(3,662)
Comprehensive income:
Net income	6,556
Other comprehensive loss	1,957
Total comprehensive income	8,513
Balance at end of period at Jun. 30, 2017	$ 347,122	$ 32,857	$ 186,154	$ 135,456	$ (1,705)	$ (5,640)