Fair Value Measurements - Significant Unobservable Inputs (Details) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Impaired loans | Discounted cash flow
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Probability of default						0.00%
Fair Value, Measurements, Nonrecurring | Impaired loans
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Fair value		$ 13,192		$ 13,797
Fair Value, Measurements, Nonrecurring | Other real estate owned
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Fair value		547		839
Fair Value, Measurements, Nonrecurring | Level III | Impaired loans
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Fair value		13,192		13,797
Fair Value, Measurements, Nonrecurring | Level III | Impaired loans | Discounted cash flow
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Fair value		$ 5,034		$ 5,304
Fair Value, Measurements, Nonrecurring | Level III | Impaired loans | Discounted cash flow | Minimum
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Temporary reduction in payment amount (as a percent)		0.00%		0.00%
Fair Value, Measurements, Nonrecurring | Level III | Impaired loans | Discounted cash flow | Maximum
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Temporary reduction in payment amount (as a percent)		(70.00%)		(70.00%)
Fair Value, Measurements, Nonrecurring | Level III | Impaired loans | Discounted cash flow | Weighted Average
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Temporary reduction in payment amount (as a percent)		(21.00%)		20.00%
Fair Value, Measurements, Nonrecurring | Level III | Impaired loans | Appraisal of collateral
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Fair value		$ 8,158		$ 8,493
Fair Value, Measurements, Nonrecurring | Level III | Impaired loans | Appraisal of collateral | Minimum
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Appraisal adjustments (as a percent)	[1]	0.00%		0.00%
Fair Value, Measurements, Nonrecurring | Level III | Impaired loans | Appraisal of collateral | Maximum
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Appraisal adjustments (as a percent)	[1]	(20.00%)		(20.00%)
Fair Value, Measurements, Nonrecurring | Level III | Impaired loans | Appraisal of collateral | Weighted Average
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Appraisal adjustments (as a percent)		(14.00%)	[2]	15.00%	[1]
Fair Value, Measurements, Nonrecurring | Level III | Other real estate owned
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Fair value		$ 547		$ 839
Fair Value, Measurements, Nonrecurring | Level III | Other real estate owned | Appraisal of collateral
Listing of significant unobservable inputs used in the fair value measurement process for items valued utilizing level III techniques
Fair value		$ 547	[2]	$ 839	[1]

[1] Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses.

[2] Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses.