Summary of Accounting Policies - Schedule of Weighted Average Diluted Shares Outstanding (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Basic weighted-average shares outstanding	102,168	101,291	100,616
Common stock awards (in shares)	1,354	1,126	887
Senior subordinated convertible notes (in shares)	0	47	94
Diluted weighted-average shares outstanding	103,522	102,464	101,597