Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands		Total		Common Stock [Member]		Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Deferred Compensation [Member]	Treasury Stock [Member]
Proceeds from issuance of common stocks	[1]	$ 57,360
Beginning Balances (shares) at Dec. 31, 2015	[2]			15,270,659
Beginning Balances at Dec. 31, 2015		358,138	[2]	$ 7,432		$ 190,311	$ 166,235	$ (5,840)	$ 1,883	$ (1,883)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		44,675					44,675
Other comprehensive income (loss)		962						962
Dividend declared		(18,848)					(18,848)
Retirement savings plan and dividend reinvestment plan (shares)				36,253
Retirement savings plan and dividend reinvestment plan		$ 2,242		$ 17		2,225
Stock issuance, shares		960,488.00		960,488	[1]
Stock issuance	[1]	$ 57,360		$ 467		56,893
Share-based compensation (shares)	[3],[4]			36,099
Share-based compensation and tax benefit	[3],[4]	1,557		$ 19		1,538
Treasury stock activities		0							533	(533)
Ending Balances (shares) at Dec. 31, 2016	[2],[5]			16,303,499
Ending Balances at Dec. 31, 2016		$ 446,086	[5]	$ 7,935		250,967	192,062	(4,878)	2,416	(2,416)
Preferred Stock, Shares Authorized		2,000,000
Preferred Stock, Par or Stated Value Per Share		$ 0.01
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		$ 32,023					32,023
Other comprehensive income (loss)		(381)						(381)
Dividend declared		(15,683)					(15,683)
Stock Issued During Period, Shares, Dividend Reinvestment Plan				10,771
Stock Issued During Period, Value, Dividend Reinvestment Plan		$ 736		$ 5		731
Stock issuance, shares		960,488
Stock issuance	[1]	$ (10)				(10)
Share-based compensation (shares)	[3],[4]			30,172
Share-based compensation and tax benefit	[3],[4]	1,049		$ 15		1,034
Treasury stock activities		0							950	(950)
Ending Balances (shares) at Sep. 30, 2017	[2],[5]			16,344,442
Ending Balances at Sep. 30, 2017		$ 463,820	[5]	$ 7,955		$ 252,722	$ 208,402	$ (5,259)	$ 3,366	$ (3,366)
Preferred Stock, Shares Authorized		2,000,000
Preferred Stock, Par or Stated Value Per Share		$ 0.01

[1] On September 22, 2016, we completed a public offering of 960,488 shares of our common stock at a price per share of $62.26. The net proceeds from the sale of common stock, after deducting underwriting commissions and expenses, were approximately $57.4 million.

[2] 2,000,000 shares of preferred stock at $0.01 par value have been authorized. None has been issued or is outstanding; accordingly, no information has been included in the statements of stockholders’ equity.

[3] Includes amounts for shares issued for Directors’ compensation.

[4] The shares issued under the SICP are net of shares withheld for employee taxes. For the nine months ended September 30, 2017, and for the year ended December 31, 2016, we withheld 10,269 and 12,031 shares, respectively, for taxes.

[5] Includes 90,588 and 76,745 shares at September 30, 2017 and December 31, 2016, respectively, held in a Rabbi Trust related to our Deferred Compensation Plan