Stockholders' Equity - Narrative (Details) - USD ($)	12 Months Ended			13 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Feb. 06, 2018
Class Of Stock [Line Items]
Stock repurchased program, authorized amount	$ 200,000,000			$ 200,000,000
Stock repurchased and retired during period, shares	2,012,000	3,240,000	4,535,000	1,911,380
Stock repurchased and retired during period, value				$ 150,000,000
Stock repurchase program, remaining authorized repurchase amount	$ 50,000,000			$ 50,000,000
New Repurchase [Member] | Subsequent Event [Member]
Class Of Stock [Line Items]
Stock repurchased program, authorized amount					$ 275,000,000
Restricted stock units (RSUs) [Member]
Class Of Stock [Line Items]
Share-based compensation arrangement by share-based payment award, non-option equity instruments, outstanding, number	874,107			874,107
Performance share units (PSUs) [Member]
Class Of Stock [Line Items]
Share-based compensation arrangement by share-based payment award, non-option equity instruments, outstanding, number	54,431			54,431