Consolidated Statements of Changes In Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Balance Beginning (in Shares) at Dec. 31, 2014		77,695,000
Balance Beginning at Dec. 31, 2014	$ 1,100,775	$ 882	$ 449,798	$ 899,516	$ (15,855)	$ (233,566)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,882			19,882
Other comprehensive income	3,050				3,050
Common dividends declared ($0.09 per common share)	(7,011)			(7,011)
Restricted stock activity (in Shares)		264,000
Restricted stock activity	(2,473)		(9,784)			7,311
Treasury stock issued to benefit plans (in Shares)		(2,000)
Treasury stock issued to benefit plans	27		(25)			52
Share-based compensation expense	1,700		1,700
Balance Ending (in Shares) at Mar. 31, 2015		77,957,000
Balance Ending at Mar. 31, 2015	$ 1,115,950	$ 882	441,689	912,387	(12,805)	(226,203)
Balance Beginning (in Shares) at Dec. 31, 2015	77,952,000	77,952,000
Balance Beginning at Dec. 31, 2015	$ 1,146,268	$ 882	446,672	953,516	(28,389)	(226,413)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	17,962			17,962
Other comprehensive income	13,348				13,348
Common dividends declared ($0.09 per common share)	(7,228)			(7,228)
Acquisition, net of issuance costs (in Shares)		3,042,000
Acquisition, net of issuance costs	54,896	$ 31	54,865
Common stock issued (in Shares)		4,000
Common stock issued	59		59
Restricted stock activity (in Shares)		303,000
Restricted stock activity	(2,546)		(10,282)			7,736
Treasury stock issued to benefit plans (in Shares)		(3,000)
Treasury stock issued to benefit plans	(33)					(33)
Share-based compensation expense	$ 1,839		1,839
Balance Ending (in Shares) at Mar. 31, 2016	81,298,000	81,298,000
Balance Ending at Mar. 31, 2016	$ 1,224,565	$ 913	$ 493,153	$ 964,250	$ (15,041)	$ (218,710)