Fair Value Measurements (Level 3 Assets Measured on a Nonrecurring Basis) (Details) $ in Thousands	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, fair value disclosure	$ 3,216,470	$ 2,098,201
Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Assets, fair value disclosure	$ 71,013	$ 63,841
Discount rate | Level 3 | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired originated loans, measurement input		0.20
Other real estate assets, measurement input		0.20
Discount rate | Level 3 | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired originated loans, measurement input		0.30
Other real estate assets, measurement input		0.30