Consolidated Statement of Changes in Stockholders' Equity - USD ($)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]	Treasury Stock [Member]
Balance at Dec. 31, 2018	$ 399,589,000	$ 127,000	$ 161,593,000	$ (2,148,000)	$ 295,588,000	$ (55,571,000)
Balance (in shares) at Dec. 31, 2018		20,171,392
Net (loss) income	11,482,000				11,482,000
Other comprehensive income (loss)	3,717,000			3,717,000
Deferred compensation plan	20,000		(22,000)			42,000
Stock based compensation expenses	11,000		11,000
Shares issued under stock option plan	185,000		(22,000)		(5,000)	212,000
Shares issued under stock option plan (in shares)		17,822
Restricted share issuance/ Restricted share activity under stock incentive plans	(311,000)		(751,000)			440,000
Restricted share issuance/Restricted share activity under stock incentive plan (in shares)		38,890
Shares issued from direct stock sales	31,000		19,000			12,000
Shares issued from direct stock sales (in shares)		1,065
Shares repurchased	(15,147,000)					(15,147,000)
Shares repurchased (In Shares)		(515,977)
Common stock dividend payment	(3,788,000)				(3,788,000)
Balance at Mar. 31, 2019	395,789,000	$ 127,000	160,828,000	1,569,000	303,277,000	(70,012,000)
Balance (in shares) at Mar. 31, 2019		19,713,192
Balance at Dec. 31, 2018	399,589,000	$ 127,000	161,593,000	(2,148,000)	295,588,000	(55,571,000)
Balance (in shares) at Dec. 31, 2018		20,171,392
Net (loss) income	36,852,000
Other comprehensive income (loss)	7,249,000
Balance at Sep. 30, 2019	418,046,000	$ 127,000	161,576,000	5,101,000	320,999,000	(69,757,000)
Balance (in shares) at Sep. 30, 2019		19,728,590
Balance at Mar. 31, 2019	395,789,000	$ 127,000	160,828,000	1,569,000	303,277,000	(70,012,000)
Balance (in shares) at Mar. 31, 2019		19,713,192
Net (loss) income	12,199,000				12,199,000
Other comprehensive income (loss)	2,598,000			2,598,000
Deferred compensation plan	17,000		(12,000)			29,000
Stock based compensation expenses	255,000		255,000
Shares issued under stock option plan	6,000		(9,000)			15,000
Shares issued under stock option plan (in shares)		1,200
Restricted share issuance/ Restricted share activity under stock incentive plans	74,000		129,000		(153,000)	98,000
Restricted share issuance/Restricted share activity under stock incentive plan (in shares)		12,304
Shares issued from direct stock sales	25,000		14,000			11,000
Shares issued from direct stock sales (in shares)		934
Common stock dividend payment	(3,747,000)				(3,747,000)
Balance at Jun. 30, 2019	407,216,000	$ 127,000	161,205,000	4,167,000	311,576,000	(69,859,000)
Balance (in shares) at Jun. 30, 2019		19,727,630
Net (loss) income	13,171,000				13,171,000
Other comprehensive income (loss)	934,000			934,000
Deferred compensation plan	19,000		(12,000)			31,000
Stock based compensation expenses	6,000		6,000
Restricted share issuance/ Restricted share activity under stock incentive plans	421,000		362,000			59,000
Shares issued from direct stock sales	27,000		15,000			12,000
Shares issued from direct stock sales (in shares)		960
Common stock dividend payment	(3,748,000)				(3,748,000)
Balance at Sep. 30, 2019	418,046,000	$ 127,000	161,576,000	5,101,000	320,999,000	(69,757,000)
Balance (in shares) at Sep. 30, 2019		19,728,590
Balance at Dec. 31, 2019	426,167,000	$ 127,000	161,955,000	4,595,000	329,175,000	(69,685,000)
Balance (in shares) at Dec. 31, 2019		19,729,886
Net (loss) income	(22,482,000)				(22,482,000)
Other comprehensive income (loss)	7,473,000			7,473,000
Adoption of ASC 326 | ASC 326 [Member]	(2,566,000)				(2,566,000)
Deferred compensation plan			(94,000)			94,000
Deferred compensation plan (in shares)		7,524
Stock based compensation expenses	1,236,000		1,230,000			6,000
Capital stock issuance related to acquisition	526,875,000	$ 179,000	526,696,000
Capital stock issuance (in shares)		17,927,017
Vesting of incentive plans	(1,496,000)		(1,989,000)			493,000
Vesting of incentive plans (in shares)		39,548
Restricted share issuance/ Restricted share activity under stock incentive plans			198,000		(374,000)	176,000
Restricted share issuance/Restricted share activity under stock incentive plan (in shares)		13,349
Restricted share forfeitures (in shares)		(750)
Shares repurchased	(10,078,000)					(10,078,000)
Shares repurchased (In Shares)		(430,000)
Common stock dividend payment	(8,286,000)				(8,286,000)
Balance at Mar. 31, 2020	916,843,000	$ 306,000	687,996,000	12,068,000	295,467,000	(78,994,000)
Balance (in shares) at Mar. 31, 2020		37,286,574
Balance at Dec. 31, 2019	426,167,000	$ 127,000	161,955,000	4,595,000	329,175,000	(69,685,000)
Balance (in shares) at Dec. 31, 2019		19,729,886
Net (loss) income	32,230,000
Other comprehensive income (loss)	9,381,000
Adoption of ASC 326 | ASC 326 [Member]	(2,600,000)
Fair value of option exchange from merger	461,000
Balance at Sep. 30, 2020	959,025,000	$ 306,000	689,736,000	13,976,000	333,772,000	(78,765,000)
Balance (in shares) at Sep. 30, 2020		37,296,613
Balance at Mar. 31, 2020	916,843,000	$ 306,000	687,996,000	12,068,000	295,467,000	(78,994,000)
Balance (in shares) at Mar. 31, 2020		37,286,574
Net (loss) income	29,057,000				29,057,000
Other comprehensive income (loss)	2,496,000			2,496,000
Deferred compensation plan			166,000			(166,000)
Stock based compensation expenses	356,000		356,000
Adjustment for capital stock issuance	(25,000)		(25,000)
Adjustment for capital stock issuance, Shares		(843)
Fair value of option exchange from merger	461,000		461,000
Prior period adjustments			(258,000)			258,000
Shares issued under stock option plan			(122,000)			122,000
Shares issued under stock option plan (in shares)		11,408
Shares repurchased	(17,000)					(17,000)
Shares repurchased (In Shares)		(1,070)
Common stock dividend payment	(8,203,000)				(8,203,000)
Balance at Jun. 30, 2020	940,968,000	$ 306,000	688,574,000	14,564,000	316,321,000	(78,797,000)
Balance (in shares) at Jun. 30, 2020		37,296,069
Net (loss) income	25,655,000				25,655,000
Other comprehensive income (loss)	(588,000)			(588,000)
Deferred compensation plan			(23,000)			23,000
Stock based compensation expenses	1,185,000		1,185,000
Shares issued from direct stock sales	9,000					9,000
Shares issued from direct stock sales (in shares)		544
Common stock dividend payment	(8,204,000)				(8,204,000)
Balance at Sep. 30, 2020	$ 959,025,000	$ 306,000	$ 689,736,000	$ 13,976,000	$ 333,772,000	$ (78,765,000)
Balance (in shares) at Sep. 30, 2020		37,296,613