CONSOLIDATED BALANCE SHEETS CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands |
Sep. 30, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Statement of Financial Position [Abstract] | ||
| Available-for-sale Securities, Amortized Cost Basis | $ 1,110,784 | $ 1,203,065 |
| Held-to-maturity Securities, Fair Value | $ 645,751 | $ 731,951 |
| Common Stock, No Par Value | $ 0 | $ 0 |
| Common Stock, Shares Authorized | 160,000,000 | 160,000,000 |
| Common Stock, Shares, Issued | 68,730,731 | 68,730,731 |
| Treasury Stock, Shares | 6,777,858 | 7,089,051 |