CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Total
Balance at Dec. 31, 2013	$ 222	$ 135,498	$ 20,463	$ (862)	$ 155,321
Balance (in shares) at Dec. 31, 2013	22,223,454
Increase (Decrease) in Stockholders' Equity
Net income			39,961		39,961
Dividends paid			(19,598)		(19,598)
Adjustment for pension and postretirement benefit liability, net of tax of $147 in 2016, ($495) in 2015 and $3,346 in 2014				(5,350)	(5,350)
Adjustment for interest rate swap, net of tax of $225 in 2016, $564 in 2015 and ($114) in 2014				184	184
Shares withheld on restricted stock vesting		(97)			(97)
Stock based compensation	$ 1	2,867			2,868
Stock based compensation (in shares)	59,174
Balance at Dec. 31, 2014	$ 223	138,268	40,826	(6,028)	173,289
Balance (in shares) at Dec. 31, 2014	22,282,628
Increase (Decrease) in Stockholders' Equity
Net income			44,176		44,176
Dividends paid			(20,173)		(20,173)
Adjustment for pension and postretirement benefit liability, net of tax of $147 in 2016, ($495) in 2015 and $3,346 in 2014				782	782
Adjustment for interest rate swap, net of tax of $225 in 2016, $564 in 2015 and ($114) in 2014				(937)	(937)
Shares withheld on restricted stock vesting		(27)			(27)
Shares issued from exercise of stock options		111			111
Shares issued from exercise of stock options (in shares)	26,350
Stock based compensation	$ 1	3,274			3,275
Stock based compensation (in shares)	78,819
Balance at Dec. 31, 2015	$ 224	141,626	64,829	(6,183)	200,496
Balance (in shares) at Dec. 31, 2015	22,387,797
Increase (Decrease) in Stockholders' Equity
Net income			39,009		39,009
Dividends paid			(21,451)		(21,451)
Adjustment for pension and postretirement benefit liability, net of tax of $147 in 2016, ($495) in 2015 and $3,346 in 2014				(231)	(231)
Adjustment for interest rate swap, net of tax of $225 in 2016, $564 in 2015 and ($114) in 2014				(258)	(258)
Stock based compensation	$ 1	2,897			2,898
Stock based compensation (in shares)	113,843
Balance at Dec. 31, 2016	$ 225	$ 144,523	$ 82,387	$ (6,672)	$ 220,463
Balance (in shares) at Dec. 31, 2016	22,501,640