Mortgage Banking Activities Mortgage Banking Activities, Loans Serviced for Others (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Serviced For Others, Current	$ 13,771,355
Loans Serviced For Others, 30 To 59 Days Past Due	156,341
Loans Serviced For Others, 60 To 89 Days Past Due	46,572
Loans Serviced For Others, Greater Than 90 Days or More Past Due	71,374
Loans Serviced For Others	14,045,642
Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Serviced For Others, Current	4,572,606
Loans Serviced For Others, 30 To 59 Days Past Due	30,870
Loans Serviced For Others, 60 To 89 Days Past Due	11,860
Loans Serviced For Others, Greater Than 90 Days or More Past Due	31,729
Loans Serviced For Others	4,647,065
Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Serviced For Others, Current	4,338,847
Loans Serviced For Others, 30 To 59 Days Past Due	19,954
Loans Serviced For Others, 60 To 89 Days Past Due	6,469
Loans Serviced For Others, Greater Than 90 Days or More Past Due	21,933
Loans Serviced For Others	4,387,203
Government National Mortgage Association Certificates and Obligations (GNMA) [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Serviced For Others, Current	4,475,395
Loans Serviced For Others, 30 To 59 Days Past Due	99,668
Loans Serviced For Others, 60 To 89 Days Past Due	26,366
Loans Serviced For Others, Greater Than 90 Days or More Past Due	12,616
Loans Serviced For Others	4,614,045
Other Investor Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Serviced For Others, Current	384,507
Loans Serviced For Others, 30 To 59 Days Past Due	5,849
Loans Serviced For Others, 60 To 89 Days Past Due	1,877
Loans Serviced For Others, Greater Than 90 Days or More Past Due	5,096
Loans Serviced For Others	$ 397,329