Revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Other operating income (in-scope of Topic 606)									$ 5,911	$ 5,826	$ 6,280
Other operating income (out-of-scope of Topic 606)									26,256	34,648	36,983
Total Other Operating Income	$ 7,718	$ 8,673	$ 8,314	$ 7,462	$ 7,952	$ 13,855	$ 9,762	$ 8,905	32,167	40,474	43,263
Bankcard fees
Disaggregation of Revenue [Line Items]
Other operating income (in-scope of Topic 606)									2,811	2,597	2,670
Service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Other operating income (in-scope of Topic 606)									1,508	1,614	1,998
Other
Disaggregation of Revenue [Line Items]
Other operating income (in-scope of Topic 606)									$ 1,592	$ 1,615	$ 1,612