Condensed Consolidated Statement of Changes in Shareholders' Equity (Unaudited) - 3 months ended Mar. 31, 2016 - USD ($) $ in Thousands	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2015	$ 453,981	$ 203	$ (22,370)	$ 204,688	$ 268,873	$ 2,587
Beginning Balance, Shares at Dec. 31, 2015	20,388,396	20,388,396
Treasury Stock Beginning Balance, Shares at Dec. 31, 2015	(1,258,250)		(1,258,250)
Comprehensive income	$ 27,050				24,257	2,793
Common stock issued upon exercise of options	$ 454			454
Common stock issued upon exercise of options, Shares	35,679	35,679
Tax benefit from share-based payments	$ 435			435
Restricted common stock issued	0	$ 0	$ 0	0	0	0
Restricted common stock issued, Shares		16,049
Share-based compensation	285			285
Dividends to shareholders	(3,452)				(3,452)
Ending Balance at Mar. 31, 2016	$ 478,753	$ 203	$ (22,370)	$ 205,862	$ 289,678	$ 5,380
Ending Balance, Shares at Mar. 31, 2016	20,440,124	20,440,124
Treasury Stock Ending Balance, Shares at Mar. 31, 2016	(1,258,250)		(1,258,250)