CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Retained Earnings	Cost of Common Stock in Treasury	Accumulated Other Comprehensive Income (Loss), Net
Balance at Dec. 31, 2014	$ 614,473	$ 0	$ 346,535	$ 302,242	$ (43,711)	$ 9,407
Increase (Decrease) in Stockholders' Equity
Net income	57,486	0	0	57,486	0	0
Other comprehensive income (loss)	(2,852)	0	0	0	0	(2,852)
Issuance of 61,899, 118,559, and 118,281 common shares under stock based compensation awards for 2017, 2016 and 2015, respectively	2,584	0	0	(245)	2,829	0
Cost of 900, 270,378, and 338,985 shares of common stock acquired for treasury for 2017, 2016 and 2015, respectively	(9,970)	0	0	0	(9,970)	0
Common stock dividend ($0.76, $0.72 and $0.671 per share for 2017, 2016 and 2015, respectively)	(17,655)	0	0	(17,655)	0	0
10% common stock dividend ($13 cash paid in lieu of fractional shares)	(13)	0	90,003	(90,016)	0	0
Balance at Dec. 31, 2015	644,053	0	436,538	251,812	(50,852)	6,555
Increase (Decrease) in Stockholders' Equity
Net income	57,786	0	0	57,786	0	0
Other comprehensive income (loss)	(5,211)	0	0	0	0	(5,211)
Issuance of 61,899, 118,559, and 118,281 common shares under stock based compensation awards for 2017, 2016 and 2015, respectively	2,808	0	0	(18)	2,826	0
Cost of 900, 270,378, and 338,985 shares of common stock acquired for treasury for 2017, 2016 and 2015, respectively	(8,030)	0	0	0	(8,030)	0
Common stock dividend ($0.76, $0.72 and $0.671 per share for 2017, 2016 and 2015, respectively)	(18,756)	0	0	(18,756)	0	0
Balance at Dec. 31, 2016	672,650	0	436,538	290,824	(56,056)	1,344
Increase (Decrease) in Stockholders' Equity
Cumulative-effect adjustment	(65)	0	0	(65)	0	0
Balance, adjusted	672,585	0	436,538	290,759	(56,056)	1,344
Net income	68,051	0	0	68,051	0	0
Other comprehensive income (loss)	(4,676)	0	0	0	0	(4,676)
Issuance of 61,899, 118,559, and 118,281 common shares under stock based compensation awards for 2017, 2016 and 2015, respectively	2,377	0	0	908	1,469	0
Cost of 900, 270,378, and 338,985 shares of common stock acquired for treasury for 2017, 2016 and 2015, respectively	(41)	0	0	0	(41)	0
Common stock dividend ($0.76, $0.72 and $0.671 per share for 2017, 2016 and 2015, respectively)	(19,759)	0	0	(19,759)	0	0
Balance at Dec. 31, 2017	$ 718,537	$ 0	$ 436,538	$ 339,959	$ (54,628)	$ (3,332)