Stock Incentive Plans - Summary of Restricted Stock Activity (Details) - Restricted Stock $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) $ / shares shares
Number of Restricted Stock
Outstanding, as of beginning of period (in shares) | shares	1,355
Granted (in shares) | shares	73
Forfeited (in shares) | shares	(9)
Vested (in shares) | shares	(6)
Outstanding, as of end of period (in shares) | shares	1,413
Weighted Average Grant Date Fair Value
Outstanding, as of beginning of period (in dollars per share) | $ / shares	$ 22.67
Granted (in dollars per share) | $ / shares	26.66
Forfeited (in dollars per share) | $ / shares	21.85
Vested (in dollars per share) | $ / shares	17.78
Outstanding, as of end of period (in dollars per share) | $ / shares	$ 22.90
Vested, total intrinsic value of restricted stock vested | $	$ 169