Securities (Securities available for sale (debt maturities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Amortized Cost
Due in 1 year or less	$ 8,858
Due in 1 to 5 years	94,678
Due in 5 to 10 years	83,887
Due after 10 years	160,693
Total debt securities	348,116
Mortgage-backed securities	1,052,695
Equity securities	5,005
Total investment securities	1,405,816	1,659,456
Estimated Fair Value
Due in 1 year or less	8,977
Due in 1 to 5 years	94,865
Due in 5 to 10 years	82,963
Due after 10 years	159,289
Total debt securities	346,094
Mortgage-backed securities	1,049,621
Equity securities	5,041
Estimated Fair Value	$ 1,400,756	$ 1,633,902