FHLB and other borrowings (Details) - Schedule of components of FHLB and other borrowings and weighted average interest rates - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
By type of borrowing:
FHLB and other borrowings (in Dollars)	$ 621,674	$ 495,553
Weighted average interest rates	1.28%	1.48%
By remaining period to maturity:
One year or less (in Dollars)	$ 290,674	$ 258,553
One year or less	0.53%	0.50%
One to two years (in Dollars)	$ 151,000	$ 30,000
One to two years	1.60%	1.40%
Two to three years (in Dollars)	$ 35,000	$ 71,000
Two to three years	1.00%	2.33%
Three to four years (in Dollars)	$ 80,000	$ 96,000
Three to four years	1.67%	2.67%
Four to five years (in Dollars)	$ 65,000
Four to five years	2.82%
Greater than five years (in Dollars)		$ 40,000
Greater than five years	0.00%	3.42%
Federal Home Loan Bank Advances [Member]
By type of borrowing:
FHLB and other borrowings (in Dollars)	$ 606,674	$ 464,553
Weighted average interest rates	1.16%	1.18%
Repurchase Agreements [Member]
By type of borrowing:
FHLB and other borrowings (in Dollars)	$ 15,000	$ 31,000
Weighted average interest rates	5.95%	5.90%