Share Repurchases (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2015
Equity [Abstract]
Stock repurchase program, authorized amount		$ 100,000,000
Stock repurchase program, remaining authorized repurchase amount	$ 49,000,000

Amount remaining of a stock repurchase plan authorized.

No definition available.

Name:	us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant