Long-Term Debt and Short-Term Borrowings - Schedule of Long-Term Debt and Short-Term Borrowings (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Aug. 13, 2015	Dec. 31, 2014	Dec. 12, 2014	Sep. 26, 2014
Senior secured term loans [Member]
Debt Instrument [Line Items]
Maturity date of debt, start	Dec. 31, 2016	Dec. 31, 2016
Maturity date of debt, end	Dec. 31, 2022	Dec. 31, 2022
Minimum [Member] | Senior secured term loans [Member]
Debt Instrument [Line Items]
Interest rate of long-term debt	1.39%	1.39%
Maximum [Member] | Senior secured term loans [Member]
Debt Instrument [Line Items]
Interest rate of long-term debt	2.22%	2.22%
5.00% Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate of long-term debt	5.00%	5.00%
5.00% Senior Notes [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate of long-term debt	5.00%	5.00%
Due date of long term debt	2023	2023
4.875% Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate of long-term debt	4.875%	4.875%	4.875%
Debt instrument, maturity date	Mar. 01, 2026
4.875% Senior Notes [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate of long-term debt	4.875%	4.875%	4.875%
Due date of long term debt	2026	2026
Debt instrument, maturity date	Mar. 01, 2026
5.25% Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate of long-term debt	5.25%	5.25%		5.25%	5.25%	5.25%
Debt instrument, maturity date	Mar. 15, 2025
5.25% Senior Notes [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate of long-term debt	5.25%	5.25%
Due date of long term debt	2025	2025
Interest at daily one- month LIBOR plus 1.60% [Member] | Warehouse Agreement Borrowings [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	May 25, 2017
Line of credit over LIBOR rate	1.60%	1.60%
Interest at daily one-month LIBOR plus 1.35% with LIBOR floor of 0.35% [Member] | Warehouse Agreement Borrowings [Member]
Debt Instrument [Line Items]
Line of credit over LIBOR rate	1.35%	1.35%
Line of credit, LIBOR floor rate	0.35%	0.35%
Interest at daily one-month LIBOR plus 1.45% [Member] | Warehouse Agreement Borrowings [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Oct. 23, 2017
Line of credit over LIBOR rate	1.45%	1.45%
Interest at daily one-month LIBOR plus 1.45% to 1.55% [Member] | Warehouse Agreement Borrowings [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Jul. 27, 2017
Interest at daily one-month LIBOR plus 1.45% to 1.55% [Member] | Minimum [Member] | Warehouse Agreement Borrowings [Member]
Debt Instrument [Line Items]
Line of credit over LIBOR rate	1.45%	1.45%
Interest at daily one-month LIBOR plus 1.45% to 1.55% [Member] | Maximum [Member] | Warehouse Agreement Borrowings [Member]
Debt Instrument [Line Items]
Line of credit over LIBOR rate	1.55%	1.55%
Interest at daily one-month LIBOR plus 1.35% [Member] | Warehouse Agreement Borrowings [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Jun. 30, 2017
Line of credit over LIBOR rate	1.35%	1.35%
Interest at daily one- month LIBOR plus 2.75% [Member] | Warehouse Agreement Borrowings [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date	Oct. 23, 2017
Line of credit over LIBOR rate	2.75%	2.75%