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, 2013	$ 585,378	$ 0	$ 346,535	$ 261,626	$ (29,364)	$ 6,581
Increase (Decrease) in Stockholders' Equity
Net income	58,069	0	0	58,069	0	0
Other comprehensive income (loss)	2,826	0	0	0	0	2,826
Issuance of 118,559, 118,281, and 91,675 common shares under stock based compensation awards, including related tax effects for 2016, 2015 and 2014, respectively	1,752	0	0	(243)	1,995	0
Cost of 270,378, 338,985, and 597,747 shares of common stock acquired for treasury for 2016, 2015 and 2014, respectively	(16,342)	0	0	0	(16,342)	0
Common stock dividend ($0.720, $0.671 and $0.645 per share for 2016, 2015 and 2014, respectively)	(17,210)	0	0	(17,210)	0	0
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 118,559, 118,281, and 91,675 common shares under stock based compensation awards, including related tax effects for 2016, 2015 and 2014, respectively	2,584	0	0	(245)	2,829	0
Cost of 270,378, 338,985, and 597,747 shares of common stock acquired for treasury for 2016, 2015 and 2014, respectively	(9,970)	0	0	0	(9,970)	0
Common stock dividend ($0.720, $0.671 and $0.645 per share for 2016, 2015 and 2014, 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 118,559, 118,281, and 91,675 common shares under stock based compensation awards, including related tax effects for 2016, 2015 and 2014, respectively	2,808	0	0	(18)	2,826	0
Cost of 270,378, 338,985, and 597,747 shares of common stock acquired for treasury for 2016, 2015 and 2014, respectively	(8,030)	0	0	0	(8,030)	0
Common stock dividend ($0.720, $0.671 and $0.645 per share for 2016, 2015 and 2014, 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