Loans and Allowance for Credit Losses Non-Performing Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Non-accrual loans	$ 117,264	$ 120,133
Loans 90 days or more past due and still accruing	14,268	11,505
Total non-performing loans	131,532	131,638
Other real estate owned (OREO)	11,906	12,815
Total non-performing assets	$ 143,438	$ 144,453