Securities (Amortized Cost and Fair Value of Securities by Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Securities Available-for-Sale: Amortized cost
Due in one year or less	$ 4,692
Due after one year through five years	16,972
Due after five years through ten years	74,720
Due after ten years	74,904
Total	609,561	626,383
Securities Available-for-Sale, Fair Value
Due in one year or less	4,740
Due after one year through five years	17,096
Due after five years through ten years	78,267
Due after ten years	78,617
Total	619,578	630,995
Securities Held-to-Maturity, Carrying Amount
Due in one year or less	0
Due after one year through five years	95
Due after five years through ten years	0
Due after ten years	0
Carrying Amount	95	184
Securities Held-to-Maturity, Fair Value
Due in one year or less	0
Due after one year through five years	95
Due after five years through ten years	0
Due after ten years	0
Total	95	186
Mortgage-backed Securities - Residential
Securities Available-for-Sale: Amortized cost
Available-for-Sale, amortized cost	437,920
Total	437,920	458,709
Securities Available-for-Sale, Fair Value
Fair value	440,505
Total	440,505	457,304
Equity Securities
Securities Available-for-Sale: Amortized cost
Available-for-Sale, amortized cost	353
Total	353	353
Securities Available-for-Sale, Fair Value
Fair value	353
Total	$ 353	$ 353