Consolidated Statements of Changes in Shareholders' Equity (USD $) In Thousands	Total	Common Stock [Member]	Capital Surplus [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance at Dec. 31, 2012	$ 1,194,565	$ 101,179	$ 916,918	$ 146,667	$ 29,801
Net income	23,945	0	0	23,945	0
Other comprehensive income (loss)	(8,983)	0	0	0	(8,983)
Dividends - common stock	(10,124)	0	0	(10,124)	0
Common stock issued	67	6	61	0	0
Common stock repurchased	(1,175)	(87)	(1,088)	0	0
Stock based compensation expense	1,023	0	1,023	0	0
Stock activity under incentive comp plans	347	269	150	(72)	0
Balance at Mar. 31, 2013	1,199,665	101,367	917,064	160,416	20,818
Balance at Dec. 31, 2013	1,162,640	99,859	900,254	206,993	(44,466)
Net income	26,510	0	0	26,510	0
Other comprehensive income (loss)	6,536	0	0	0	6,536
Dividends - common stock	(10,997)	0	0	(10,997)	0
Common stock issued	78	5	73	0	0
Common stock repurchased	(1,576)	(116)	(1,460)	0	0
Stock based compensation expense	1,028	0	1,028	0	0
Stock activity under incentive comp plans	1,018	336	770	(88)	0
Balance at Mar. 31, 2014	$ 1,185,237	$ 100,084	$ 900,665	$ 222,418	$ (37,930)