CONSOLIDATED BALANCE SHEETS CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Available-for-sale Securities, Amortized Cost Basis	$ 887,692	$ 945,052
Held-to-maturity Securities, Fair Value	$ 885,327	$ 824,985
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	11,020,794	11,197,685