Loans (Summary of Loans) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Summary of loans under portfolio
Commercial loan	$ 2,586,653	$ 2,518,826	$ 2,298,505
Consumer loan	2,166,636	2,128,795	1,886,756
Total loans	4,753,289	4,647,621	4,185,261
Commercial [Member]
Summary of loans under portfolio
Commercial loan	1,208,641	1,176,307	1,038,115
Real estate commercial [Member]
Summary of loans under portfolio
Commercial loan	1,279,167	1,232,658	1,162,383
Real estate construction [Member]
Summary of loans under portfolio
Commercial loan	85,084	89,795	65,367
Land development [Member]
Summary of loans under portfolio
Commercial loan	13,761	20,066	32,640
Real estate residential [Member]
Summary of loans under portfolio
Consumer loan	962,009	960,423	872,454
Consumer installment [Member]
Summary of loans under portfolio
Consumer loan	675,412	644,769	540,216
Home equity [Member]
Summary of loans under portfolio
Consumer loan	$ 529,215	$ 523,603	$ 474,086