Earnings Per Share - Calculation of Fully Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Fully diluted (loss) earnings per share
Net income (loss) available to common stockholders	$ 35,039	$ 52,920	$ 93,813	$ 89,745
Allocations of net income (loss) to limited partnership interests, net of tax	15,406	28,952	45,389	48,761
Net income (loss) for fully diluted shares	$ 50,445	$ 81,872	$ 139,202	$ 138,506
Weighted-average shares:
Common stock outstanding	321,199	286,840	314,501	285,129
Partnership units	158,740	163,327	163,942	161,311
RSUs (Treasury stock method)	311	409	454	525
Other	1,211	1,281	1,296	1,382
Fully diluted weighted-average shares of common stock outstanding	481,461	451,857	480,193	448,347
Fully diluted earnings (loss) per share	$ 0.10	$ 0.18	$ 0.29	$ 0.31