Employee Benefits and Share-Based Compensation - Stock Repurchase Program (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Aug. 02, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares acquired (in shares)	0	0	0	0
The 2016 Repurchase Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase, authorized amount					$ 50,000,000.0
2016 and 2014 Share Repurchase Programs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase, remaining authorized repurchase amount	$ 54,900,000		$ 54,900,000