Earnings Per Share (Schedule of Earnings Per Share) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net income attributable to the Company	$ 81,565		$ 75,542		$ 93,347		$ 37,632		$ 80,511		$ 80,705		$ 50,594		$ 21,724		$ 288,086	$ 233,534	$ 186,367
Less: dividends and undistributed earnings allocated to unvested RSUs																	321	514	324
Net income allocated to common stockholders																	$ 287,765	$ 233,020	$ 186,043
Basic weighted-average shares																	108,427	106,884	106,991
Effect of dilutive employee stock options and RSUs																	1,399	1,804	2,111
Diluted weighted-average shares																	109,826	108,688	109,102
Basic	$ 0.75	[1]	$ 0.69	[1]	$ 0.86	[1]	$ 0.35	[1]	$ 0.75	[1]	$ 0.75	[1]	$ 0.47	[1]	$ 0.20	[1]	$ 2.65	$ 2.18	$ 1.74
Diluted	$ 0.74	[1]	$ 0.69	[1]	$ 0.85	[1]	$ 0.34	[1]	$ 0.74	[1]	$ 0.74	[1]	$ 0.47	[1]	$ 0.20	[1]	$ 2.62	$ 2.15	$ 1.71

[1] Net income per share attributable to the Company’s stockholders for the four quarters of each fiscal year may not sum to the total for the fiscal year because of the different number of shares outstanding during each period.