Loans (Summary of Loans) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Summary of loans under portfolio
Commercial loan	$ 4,396,882	$ 4,250,117	$ 4,110,698
Consumer loan	3,250,387	3,021,030	2,924,045
Total loans	7,647,269	7,271,147	7,034,743
Commercial [Member]
Summary of loans under portfolio
Commercial loan	1,953,301	1,905,879	1,754,873
Real estate commercial [Member]
Summary of loans under portfolio
Commercial loan	2,157,733	2,112,162	2,243,513
Real estate construction [Member]
Summary of loans under portfolio
Commercial loan	285,848	232,076	112,312
Real estate residential [Member]
Summary of loans under portfolio
Consumer loan	1,494,192	1,429,636	1,310,167
Consumer installment [Member]
Summary of loans under portfolio
Consumer loan	1,048,622	877,457	887,907
Home equity [Member]
Summary of loans under portfolio
Consumer loan	$ 707,573	$ 713,937	$ 725,971