CONSOLIDATED STATEMENTS OF SHAREHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Treasury Stock [Member]
Balance at Dec. 31, 2016	$ 414,395	$ 1,820	$ 74,525	$ 421,826	$ (14,164)	$ (69,612)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	26,515	0	0	26,515	0	0
Other comprehensive income (loss)	8,733	0	0	0	8,733	0
Omnibus Equity Incentive Plan	530	2	528	0	0	0
Payments for Repurchase of Common Stock	(503)		0	0	0
Dividends, Common Stock, Cash	(6,112)	0	0	(6,112)	0	0
Balance at Sep. 30, 2017	443,558	1,822	75,053	442,229	(5,431)	(70,115)
Balance at Jun. 30, 2017	434,454	1,821	74,877	433,435	(5,564)	(70,115)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	8,794	0	0	8,794	0	0
Other comprehensive income (loss)	133	0	0	0	133	0
Omnibus Equity Incentive Plan	177	1	176	0	0	0
Dividends, Common Stock, Cash	0			0
Balance at Sep. 30, 2017	443,558	1,822	75,053	442,229	(5,431)	(70,115)
Balance at Dec. 31, 2017	413,569	1,822	75,624	420,275	(14,704)	(69,448)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	35,527	0	0	35,527	0	0
Other comprehensive income (loss)	(15,240)	0	0	0	(15,240)	0
Omnibus Equity Incentive Plan	559	2	557	0	0	0
Payments for Repurchase of Common Stock	(391)		0	0	0
Dividends, Common Stock, Cash	(6,250)	0	0	(6,250)	0	0
Balance at Sep. 30, 2018	427,774	1,824	76,181	451,918	(32,310)	(69,839)
Balance at Jun. 30, 2018	419,695	1,823	75,995	440,605	(28,889)	(69,839)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	11,313	0	0	11,313	0	0
Other comprehensive income (loss)	(3,421)	0	0	0	(3,421)	0
Omnibus Equity Incentive Plan	187	1	186	0	0	0
Dividends, Common Stock, Cash	0			0
Balance at Sep. 30, 2018	$ 427,774	$ 1,824	$ 76,181	$ 451,918	$ (32,310)	$ (69,839)