|
Loans and reserve for credit losses (Average Recorded Investment in Impaired Financing Receivables) (Details) (USD $)
In Thousands, unless otherwise specified
|
12 Months Ended |
|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
| Financing Receivable, Impaired [Line Items] |
|
|
|
| Impaired Financing Receivable, Average Recorded Investment |
$ 34,367 |
$ 49,980 |
$ 73,710 |
| Commercial Real Estate Owner Occupied |
|
|
|
| Financing Receivable, Impaired [Line Items] |
|
|
|
| Impaired Financing Receivable, Average Recorded Investment |
6,115 |
12,922 |
15,521 |
| Commercial Real Estate Non Owner Occupied |
|
|
|
| Financing Receivable, Impaired [Line Items] |
|
|
|
| Impaired Financing Receivable, Average Recorded Investment |
22,699 |
25,655 |
33,267 |
| Commercial real estate |
|
|
|
| Financing Receivable, Impaired [Line Items] |
|
|
|
| Impaired Financing Receivable, Average Recorded Investment |
28,814 |
38,577 |
48,788 |
| Construction |
|
|
|
| Financing Receivable, Impaired [Line Items] |
|
|
|
| Impaired Financing Receivable, Average Recorded Investment |
1,157 |
2,283 |
7,272 |
| Residential real estate |
|
|
|
| Financing Receivable, Impaired [Line Items] |
|
|
|
| Impaired Financing Receivable, Average Recorded Investment |
381 |
1,596 |
5,685 |
| Commercial and industrial |
|
|
|
| Financing Receivable, Impaired [Line Items] |
|
|
|
| Impaired Financing Receivable, Average Recorded Investment |
4,015 |
7,039 |
10,500 |
| Consumer |
|
|
|
| Financing Receivable, Impaired [Line Items] |
|
|
|
| Impaired Financing Receivable, Average Recorded Investment |
$ 0 |
$ 485 |
$ 1,465 |