Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Other Assets [Abstract]
Cash surrender value of bank-owned life insurance	$ 338,002	$ 286,109
Accrued interest receivable	65,218	64,058
Accounts receivable	19,692	23,461
FHLB and FRB stock	68,288	78,065
Private equity investments	28,018	28,363
Prepaid expenses	33,348	33,198
Derivative asset positions	27,139	32,117
Other properties held for sale	10,671	12,227
Servicing asset	4,287	3,323
Miscellaneous other assets	55,982	54,963
Total other assets	$ 650,645	$ 615,884