Incentive Plan - Summary of Non-Vested Shares (Details)	12 Months Ended
	Dec. 31, 2017 $ / shares shares
Number of Shares
Nonvested at beginning of period (in shares) | shares	539,606
Granted during period (in shares) | shares	860,402
Vested during period (in shares) | shares	(300,300)
Forfeited during period (in shares) | shares	(2,698)
Nonvested at end of period (in shares) | shares	1,097,010
Weighted Average Grant Date, Fair Value Per Share
Nonvested at beginning of period (in dollars per share) | $ / shares	$ 36.55
Granted during period (in dollars per share) | $ / shares	41.37
Vested during period (in dollars per share) | $ / shares	35.93
Forfeited during period (in dollars per share) | $ / shares	36.55
Nonvested at end of period (in dollars per share) | $ / shares	$ 40.50