Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Additional Paid- in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2015	$ 652,405	$ 190,750		$ 395	$ 1	$ 429,790	$ 63,534	$ (29,070)	$ (2,995)
Comprehensive income:
Net income	19,687						19,687
Other comprehensive income, net	5,830								5,830
Issuance of stock		120,258	$ 75,531	60	0	75,471
Stock option compensation expense	138					138
Restricted stock compensation expense	3,653					3,653
Stock appreciation right expense	13					13
Restricted stock surrendered due to employee tax liability	(193)			(1)		(192)
Tax effect from stock compensation plan	192					192
Shares purchased under the Dividend Reinvestment Plan	8					58	(50)
Stock appreciation right dividend equivalents	(186)						(186)
Dividends declared	(5,231)						(5,231)
Preferred stock dividends	(4,575)						(4,575)
Ending Balance at Mar. 31, 2016	867,530	311,008		454	1	509,123	73,179	(29,070)	2,835
Beginning Balance at Dec. 31, 2016	980,239	269,071		537	2	614,226	134,515	(29,070)	(9,042)
Comprehensive income:
Net income	17,201						17,201
Other comprehensive income, net	(660)								(660)
Issuance of stock			$ 0	1	1	(2)
Stock option compensation expense	247					247
Restricted stock compensation expense	2,604					2,604
Stock appreciation right expense	42					42
Restricted stock surrendered due to employee tax liability	(2,135)			(1)		(2,134)
Stock appreciation right dividend equivalents	(203)						(203)
Dividends declared	(6,474)						(6,474)
Preferred stock dividends	(5,113)						(5,113)
Ending Balance at Mar. 31, 2017	$ 985,748	$ 269,071		$ 537	$ 3	$ 614,983	$ 139,926	$ (29,070)	$ (9,702)