Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Income tax expense	$ 5,544,000	$ 13,263,000	$ 9,477,000	$ 17,162,000
Annual effective tax rate			35.20%
Tax rate impact on income			2,700,000
Deferred tax asset	0		0		4,436,000
Deferred tax liability	$ 3,326,000		$ 3,326,000		$ 0