Consolidated statements of changes in shareholders' equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income, Net
Balance at Dec. 31, 2013	$ 189,687	$ 17,180	$ 94,544	$ 82,375	$ (4,412)
Net income	32,462			32,462
Other comprehensive income (loss), net of taxes	9,679				9,679
Cash dividends declared	(16,600)			(16,600)
Balance at Dec. 31, 2014	215,228	17,180	94,544	98,237	5,267
Net income	47,856			47,856
Other comprehensive income (loss), net of taxes	(2,810)				(2,810)
Cash dividends declared	(23,600)			(23,600)
Balance at Dec. 31, 2015	236,674	17,180	94,544	122,493	2,457
Net income	40,591			40,591
Other comprehensive income (loss), net of taxes	(3,331)				(3,331)
Common stock issued, net of offering costs	115,525	6,765	108,760
Conversion of cash to stock-settled awards for, Equity based incentive plans	2,388		2,388
Conversion of cash to stock-settled awards for, Deferred compensation plan	3,000		3,000
Stock based compensation expense	4,693		4,693
Restricted stock units vested and distributed, net of shares withheld for taxes	(271)	142	(413)
Shares issued under employee stock purchase program	529	21	508
Cash dividends declared	(69,300)			(69,300)
Balance at Dec. 31, 2016	$ 330,498	$ 24,108	$ 213,480	$ 93,784	$ (874)