Goodwill, Intangible Assets and Deferred Charge - Schedule of Goodwill, Intangible Assets and Deferred Charges (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Roll Forward]
Goodwill, Beginning balance	$ 73,071	$ 60,071
Goodwill, Acquired during the year	0	13,000
Goodwill, Ending balance	73,071	73,071	$ 60,071
Finite-lived Intangible Assets [Roll Forward]
Intangible assets with a definite life, Amortization	(12,200)	(5,800)	(21,200)
Indefinite-lived Intangible Assets [Roll Forward]
Intangible assets with an indefinite life, Beginning balance	87,031	63,000
Intangible assets with an indefinite life, Acquired during the year	0	24,031
Intangible assets with an indefinite life, Ending balance	87,031	87,031	63,000
Goodwill and Intangible Assets [Roll Forward]
Goodwill and intangible assets, Beginning Balance	201,150	150,071
Goodwill and intangible assets, Acquired during the year	0	57,031
Intangible assets with a definite life, Amortization	(12,200)	(5,800)	(21,200)
Goodwill and intangible assets, Ending balance	191,304	201,150	150,071
Deferred Charges [Roll Forward]
Other assets - Deferred Charge, Beginning balance	0	0
Other assets - Deferred Charge, Acquired during the year	271,176	0
Other assets - Deferred Charge, Amortization	(15,265)	0
Other assets - Deferred Charge, Ending balance	255,911	0	0
Fair Value Adjustments
Finite-lived Intangible Assets [Roll Forward]
Intangible assets with a definite life, Beginning balance	159,095	223,947
Intangible assets with a definite life, Acquired during the year	23,968	(65,000)
Intangible assets with a definite life, Amortization	(2,333)	148
Intangible assets with a definite life, Ending balance	180,730	159,095	223,947
Goodwill and Intangible Assets [Roll Forward]
Intangible assets with a definite life, Amortization	(2,333)	148
Other
Finite-lived Intangible Assets [Roll Forward]
Intangible assets with a definite life, Beginning balance	41,048	27,000
Intangible assets with a definite life, Acquired during the year	0	20,000
Intangible assets with a definite life, Amortization	(9,846)	(5,952)
Intangible assets with a definite life, Ending balance	31,202	41,048	$ 27,000
Goodwill and Intangible Assets [Roll Forward]
Intangible assets with a definite life, Amortization	$ (9,846)	$ (5,952)