Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes Disclosure [Line Items]
Deferred tax liabilities, net, current	$ 0	$ 0
Deferred tax liabilities, net, noncurrent	$ 54,641	$ 58,529
Effective income tax rate	47.20%	53.20%	37.60%
Tax rate change (as a percent)	5.20%	7.80%	1.50%
Other adjustments (as a percent)	2.20%	0.30%	0.10%
Valuation allowance related to operating loss carryforwards	$ 600	$ 1,900
Current tax expense (benefit)	$ 13,361	(26,263)	$ 14,617
Tax credit carryforwards expiration period	2021
Valuation allowance related to tax credit carryforwards	$ 4,700	5,000
Decrease in valuation allowance amount	1,700	(1,800)	(3,700)
Increase in valuation allowance amount	(1,700)	1,800	3,700
Employment tax credit	10,500
Unrecognized tax benefits	2,618	2,471	$ 2,300	$ 2,710
Unrecognized tax benefits, income tax penalties and interest accrued	800	800
Canadian Subsidiary
Income Taxes Disclosure [Line Items]
Undistributed earnings	2,600
Uncertain Tax Positions
Income Taxes Disclosure [Line Items]
Unrecognized tax benefits	3,300	3,200
Net Operating Loss Carryforwards
Income Taxes Disclosure [Line Items]
Current tax expense (benefit)	3,900	24,300
Stock Option Exercises And Net Operating Loss Carryforward
Income Taxes Disclosure [Line Items]
Current tax expense (benefit)	20,700
Domestic Tax Authority
Income Taxes Disclosure [Line Items]
Net operating loss carryforwards	$ 100
Net operating loss carryforwards, expiration period	2031
State and Local Jurisdiction
Income Taxes Disclosure [Line Items]
Change in state and local income taxes (as a percent)	2.80%
Net operating loss carryforwards	$ 60,800
Net operating loss carryforwards, expiration period	2016
Operating loss carryforwards expire because of annual limitation	$ 2,700
Tax credit carryforwards	6,500
State and Local Jurisdiction | Net Operating Loss Carryforwards
Income Taxes Disclosure [Line Items]
Stock option excess tax benefits	$ 14,100
New Accounting Pronouncement, Early Adoption, Effect [Member]
Income Taxes Disclosure [Line Items]
Deferred tax liabilities, net, current		(65,700)
Deferred tax assets, net, noncurrent		7,200
Deferred tax liabilities, net, noncurrent		$ 58,500