Loans (Summary of Loans) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Summary of loans under portfolio
Commercial loan	$ 2,622,872	$ 2,518,826	$ 2,364,870
Consumer loan	2,275,932	2,128,795	1,971,001
Total loans	4,898,804	4,647,621	4,335,871
Commercial [Member]
Summary of loans under portfolio
Commercial loan	1,212,383	1,176,307	1,091,894
Real estate commercial [Member]
Summary of loans under portfolio
Commercial loan	1,298,365	1,232,658	1,172,347
Real estate construction [Member]
Summary of loans under portfolio
Commercial loan	101,168	89,795	73,448
Land development [Member]
Summary of loans under portfolio
Commercial loan	10,956	20,066	27,181
Real estate residential [Member]
Summary of loans under portfolio
Consumer loan	970,397	960,423	898,816
Consumer installment [Member]
Summary of loans under portfolio
Consumer loan	744,781	644,769	577,241
Home equity [Member]
Summary of loans under portfolio
Consumer loan	$ 560,754	$ 523,603	$ 494,944