Loans and Allowance for Loan Losses (Details 3) - Acquired loans - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Credit impaired
Contractual loan payments receivable, estimates of amounts not expected to be collected, other fair value adjustments and the resulting fair values of acquired loans
Contractual principal and interest	$ 1,093,583	$ 1,337,703	$ 1,463,643
Non-accretable difference	(64,121)	(104,110)	(189,514)
Cash flows expected to be collected	1,029,462	1,233,593	1,274,129
Accretable Yield	(200,792)	(306,826)	(217,634)
Total acquired loans	828,670	926,767	1,056,495
Allowance for loan losses on acquired loans	(4,689)	(7,365)	(9,159)
Non-Credit impaired
Contractual loan payments receivable, estimates of amounts not expected to be collected, other fair value adjustments and the resulting fair values of acquired loans
Total acquired loans	$ 1,171,672	$ 1,327,999	$ 1,447,583