Accumlated other comprehensive income table (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment	[1]	$ 0
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		0	[2]	$ 177	[3]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance		(1,831)		(1,337)		$ (2,452)
Total other comprehensive income (loss)		1,886		(494)		1,115
Ending Balance		(1,173)		(1,831)		(1,337)
Unrealized Gain (Loss) on Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment		(111)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		(831)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance		(504)		173		1,306
Total other comprehensive income (loss)		(4,501)		(677)		(1,133)
Ending Balance		(5,947)		(504)		173
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment		205
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		0
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance				361
Total other comprehensive income (loss)		4,995
Ending Balance						361
Unrealized Gain (Loss) on Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance		948				(1,955)
Total other comprehensive income (loss)				587		2,316
Ending Balance		6,148		948
Deferred Gain on Hedge Transactions
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment		29
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		0
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance		137		281		427
Total other comprehensive income (loss)		(166)		(144)		(146)
Ending Balance		0		137		281
Defined Benefit Postretirement Plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment		(520)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets		0
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance		(2,412)		(2,152)		(2,230)
Total other comprehensive income (loss)		1,558		(260)		78
Ending Balance		(1,374)		(2,412)		(2,152)
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Prior Period Reclassification Adjustment	[2]	(397)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	[1]	(831)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Total other comprehensive income (loss)		$ 1,886		$ (494)		$ 1,115

[1] Represents adjustment needed to reflect the cumulative impact on retained earnings for the classification and measurement of investments in equity securities. Pursuant to the Company's adoption of Accounting Standards Update 2016-01, the Company's investments in equity securities will no longer be classified as available for sale, therefore the Company was required to reclassify the net unrealized gain recognized on the change in fair value of these equity securities from other comprehensive income to retained earnings.

[2] Represents adjustment needed to reflect the cumulative impact on retained earnings for reclassification of the income tax effects attributable to accumulated other comprehensive income, as a result of the Tax Cuts and Jobs Act (the "Tax Act"). Pursuant to the Company's adoption of Accounting Standards Update 2018-02, the Company has elected to reclassify amounts stranded in other comprehensive income to retained earnings.

[3] Represents adjustment needed to reflect the cumulative impact on retained earnings for previously recognized stock based compensation, which included an adjustment for estimated forfeitures. Pursuant to the Company's adoption of Accounting Standards Update 2016-09, the Company has elected to recognize stock based compensation without inclusion of a forfeiture estimate, and as such has recognized this adjustment to present retained earnings consistent with this election.