Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	COMMON STOCK	RETAINED EARNINGS	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	TREASURY STOCK, AT COST
Balance at beginning of year at Dec. 31, 2017		$ 186,903	$ 59,208	$ 596	$ (4,633)
Cumulative effect adjustment upon adoption of ASU 2016-01 at Dec. 31, 2017			169	(169)
Beginning balance adjusted at Dec. 31, 2017			59,377	427
Issued treasury shares under the Long Term Incentive Plan		(2,238)
Stock compensation expense for unvested shares		1,175
Net income	$ 23,883		23,883
Dividends declared			(6,095)
Other comprehensive income (loss)	(11,098)			(11,098)
Purchased shares					0
Issued shares under the Long Term Incentive Plan					2,238
Retained shares to cover tax withholdings under the Long Term Incentive Plan					(1,150)
Balance at end of year at Sep. 30, 2018	248,789	185,840	77,165	(10,671)	(3,545)
Balance at beginning of year at Jun. 30, 2018		186,931	71,305	(6,799)	(3,927)
Issued treasury shares under the Long Term Incentive Plan		(1,532)
Stock compensation expense for unvested shares		441
Net income	8,084		8,084
Dividends declared			(2,224)
Other comprehensive income (loss)	(3,872)			(3,872)
Purchased shares					0
Issued shares under the Long Term Incentive Plan					1,532
Retained shares to cover tax withholdings under the Long Term Incentive Plan					(1,150)
Balance at end of year at Sep. 30, 2018	248,789	185,840	77,165	(10,671)	(3,545)
Balance at beginning of year at Dec. 31, 2018	262,320	186,163	83,630	(4,030)	(3,443)
Cumulative effect adjustment upon adoption of ASU 2016-01 at Dec. 31, 2018			0	0
Beginning balance adjusted at Dec. 31, 2018			83,630	(4,030)
Issued treasury shares under the Long Term Incentive Plan		(1,169)
Stock compensation expense for unvested shares		1,024
Net income	26,085		26,085
Dividends declared			(7,771)
Other comprehensive income (loss)	15,024			15,024
Purchased shares					(2,842)
Issued shares under the Long Term Incentive Plan					1,169
Retained shares to cover tax withholdings under the Long Term Incentive Plan					(617)
Balance at end of year at Sep. 30, 2019	293,223	186,018	101,944	10,994	(5,733)
Balance at beginning of year at Jun. 30, 2019		185,687	95,557	7,877	(4,296)
Issued treasury shares under the Long Term Incentive Plan		(29)
Stock compensation expense for unvested shares		360
Net income	9,154		9,154
Dividends declared			(2,767)
Other comprehensive income (loss)	3,117			3,117
Purchased shares					(1,454)
Issued shares under the Long Term Incentive Plan					29
Retained shares to cover tax withholdings under the Long Term Incentive Plan					(12)
Balance at end of year at Sep. 30, 2019	$ 293,223	$ 186,018	$ 101,944	$ 10,994	$ (5,733)