Consolidated statements of changes in shareholders' equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss), Net
Balance at Dec. 31, 2016	$ 330,498	$ 24,108	$ 213,480	$ 93,784	$ (874)
Initial fair value election on mortgage servicing rights, net of taxes of $396 (See Note 1)	615			615
Net income	20,992			20,992
Other comprehensive income (loss), net of taxes	2,162				2,162
Common stock issued, net of offering costs	152,721	4,807	147,914
Stock-based compensation expense	3,154	6	3,148
Restricted stock units vested and distributed, net of shares withheld for taxes	(625)	47	(672)
Balance at Jun. 30, 2017	509,517	28,968	363,870	115,391	1,288
Balance at Dec. 31, 2017	596,729	30,536	418,596	147,449	148
Initial adoption of ASU 2016-01 (See Note 1)				(109)	109
Net income	41,819			41,819
Other comprehensive income (loss), net of taxes	(7,613)				(7,613)
Stock-based compensation expense	3,819	6	3,813
Restricted stock units vested and distributed, net of shares withheld for taxes	(2,555)	124	(2,679)
Shares issued under employee stock purchase program	669	17	652
Dividends declared ($0.06 per share)	(1,909)			(1,909)
Balance at Jun. 30, 2018	$ 630,959	$ 30,683	$ 420,382	$ 187,250	$ (7,356)