Fair Value Measurements - Fair Value of Assets on a Nonrecurring Basis (Details) - Nonrecurring - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	$ 56,829	$ 73,518
Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	56,829	73,518
Impaired loans
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	54,060	70,619
Impaired loans | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	54,060	70,619
Other real estate and repossessed assets
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	2,769	2,899
Other real estate and repossessed assets | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	$ 2,769	$ 2,899