Investments (Amortized Cost and Estimated Fair Values of Investments Held-To-Maturity) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 221,690	$ 224,638
Gross Unrealized Gains	4,148	1,949
Gross Unrealized Losses	(2,708)	(10,580)
Estimated Fair Value	223,130	216,007
U.S. Government Agencies [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	64,510	64,505
Gross Unrealized Losses	(1,984)	(4,827)
Estimated Fair Value	62,526	59,678
State and Municipal [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	156,971	159,889
Gross Unrealized Gains	4,121	1,920
Gross Unrealized Losses	(724)	(5,753)
Estimated Fair Value	160,368	156,056
Mortgage-Backed [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	209	244
Gross Unrealized Gains	27	29
Estimated Fair Value	$ 236	$ 273