Fair Value Measurements - Quantitative Information, Level 3 (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Nonrecurring | Impaired Loans
Fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans	$ 359	$ 1,634
Level 3
Fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans	2,725,031	2,675,811
Level 3 | Nonrecurring | Impaired Loans
Fair value measurements for financial instruments measured at fair value on a non-recurring basis
Impaired loans	$ 359	$ 1,634
Valuation Technique(s)	Market approach	Market approach
Unobservable Input(s)	Adjustment for differences between the comparable sales	Adjustment for differences between the comparable sales
Level 3 | Nonrecurring | Impaired Loans | Minimum
Fair value measurements for financial instruments measured at fair value on a non-recurring basis
Range of Inputs; Weighted Average	(23.80%)	23.80%
Level 3 | Nonrecurring | Impaired Loans | Maximum
Fair value measurements for financial instruments measured at fair value on a non-recurring basis
Range of Inputs; Weighted Average	23.00%	63.90%
Level 3 | Nonrecurring | Impaired Loans | Weighted Average
Fair value measurements for financial instruments measured at fair value on a non-recurring basis
Range of Inputs; Weighted Average	(2.60%)	20.40%