Securities (Amortized cost and fair value of debt securities by contractrual maturity) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Available-for-sale Securities
Securities available for sale, amortized cost	$ 580,339	$ 611,331
Available-for-sale securities, fair value	566,837	585,923
Held-to-maturity Securities
Securities held to maturity, amortized cost	278,019	283,814
Securities held to maturity, fair value	268,243	263,697
Debt Securities [Member]
Held-to-maturity Securities
Due in one year or less, amortized cost	0
Due after one year through five years, amortized cost	5,000
Due after five years through ten years, amortized cost	71,018
Due after ten years, amortized cost	82,081
Securities held to maturity, amortized cost	158,099
Due in one year or less, fair value	0
Due after one year through five years, fair value	5,116
Due after five years through ten years, fair value	66,702
Due after ten years, fair value	78,011
Securities held to maturity, fair value	149,829
Residential mortgage-backed securities [Member]
Held-to-maturity Securities
Securities held to maturity, amortized cost	7,515	7,849
Securities held to maturity, fair value	7,920	8,046
Agency CMOs [Member]
Held-to-maturity Securities
Securities held to maturity, amortized cost	112,405	118,893
Securities held to maturity, fair value	110,494	114,679
Debt Securities [Member]
Available-for-sale Securities
Due in one year or less, amortized cost	0
Due after one year through five years, amortized cost	3,878
Due after five years through ten years, amortized cost	48,682
Due after ten years, amortized cost	9,391
Securities available for sale, amortized cost	61,951
Due in one year or less, fair value	0
Due after one year through five years, fair value	3,821
Due after five years through ten years, fair value	46,266
Due after ten years, fair value	9,101
Available-for-sale securities, fair value	59,188
Residential mortgage-backed securities [Member]
Available-for-sale Securities
Securities available for sale, amortized cost	63,580	65,795
Available-for-sale securities, fair value	62,737	62,500
Agency CMOs [Member]
Available-for-sale Securities
Securities available for sale, amortized cost	454,808	483,591
Available-for-sale securities, fair value	$ 444,912	$ 467,064