Net Income Per Share Reconciliation of Weighted Average Common Shares Outstanding (Details) - $ / shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average shares outstanding (basic) (in shares)	168,343	175,764	169,109	175,535
Impact of common stock equivalents (in shares)	825	1,080	933	1,171
Weighted average shares outstanding (diluted) (in shares)	169,168	176,844	170,042	176,706
Basic (in dollars per share)	$ 0.36	$ 0.20	$ 0.69	$ 0.48
Diluted (in dollars per share)	$ 0.35	$ 0.20	$ 0.68	$ 0.48