Borrowings (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Advances from FHLB
FHLB Advances, Weighted Rate, within one year	0.28%	0.68%
FHLB Advances, Maturing within one year	$ 720,000	$ 792,000
FHLB Advances, Weighted Rate, two years through three years	3.48%
FHLB Advances, Maturing two years through three years	75,000
FHLB Advances, Weighted Rate, three years through four years	2.99%	3.48%
FHLB Advances, Maturing three years through four years	45,000	75,000
FHLB Advances, Weighted Rate, four years through five years		2.99%
FHLB Advances, Maturing four years through five years		45,000
FHLB Advances, Weighted Rate, Thereafter	3.07%	3.07%
FHLB Advances, Maturing Thereafter	157,013	157,046
FHLB Advances, Weighted Rate	1.09%	1.32%
FHLB Advances, Maturity Amount, Total	$ 997,013	$ 1,069,046