Employee Benefits and Stock Compensation - Employee Stock Purchase Plan (Details) - $ / shares	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ESPP shares purchased	243,391	63,650	413,000
Employee Stock Option [Member]
ESPP shares purchased	10,483	9,083	13,294
Weighted-average employee purchase price	$ 16.02	$ 13.99	$ 10.63

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

No definition available.

Name:	us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration