Organization, Operations and Basis of Presentation (Details)		3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 16, 2016	Sep. 30, 2018 USD ($) $ / shares shares	Sep. 30, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	May 04, 2018 USD ($)	Oct. 01, 2016 $ / shares
Accounting Policies [Abstract]
Common stock par value (in dollars per share) | $ / shares		$ 0.01	$ 0.01	$ 0.01		$ 0.01
Shares received, conversion ratio	0.04
Liabilities to creditors, payments issued but outstanding			$ 8,200,000	$ 8,500,000
Share repurchase program, maximum amount of shares authorized to be repurchased					$ 75,000,000
Common stock, shares outstanding (in shares) | shares		29,991,468	29,991,468	30,482,966
Stock repurchased during period (in shares) | shares		475,175	545,282
Stock repurchased during period, value		$ 17,300,000	$ 19,700,000
Treasury stock acquired, weighted average cost per share (in dollars per share) | $ / shares		$ 35.70	$ 36.06
Stock repurchase program, remaining authorized repurchase amount		$ 55,300,000	$ 55,300,000