Stock Incentive Plans - Stock Option Activity (Details) - Stock Option - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Number Of Shares (in thousands)
Outstanding, beginning balance (in shares)	2,122
Options exercised (in shares)	325
Options forfeited (in shares)	4
Options granted (in shares)	235
Outstanding, end balance (in shares)	2,028	2,122
Exercisable, end of period (in shares)	814
Weighted Average Exercise Price
Outstanding, beginning balance (in usd per share)	$ 16.92
Options exercised (in usd per share)	12.73
Options forfeited (in usd per share)	18.79
Options granted (in usd per share)	26.40
Outstanding, ending balance (in usd per share)	18.69	$ 16.92
Exercisable, end of period (in usd per share)	$ 17.05
Other Disclosures
Outstanding, weighted-average remaining contractual term	4 years 26 days	3 years 6 months 26 days
Exercisable, weighted-average remaining contractual term	2 years 10 months 21 days
Outstanding, aggregated intrinsic value	$ 28,863	$ 20,748
Exercisable, aggregated intrinsic value	$ 5,776