Income Taxes (Narrative) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Loss Carryforwards [Line Items]
Excess tax benefit associated with equity based compensation	$ 5,196	$ 2,069	$ 7,518
Increase (decrease) to tax expense		(3,869)	$ 1,220
Additional Increase to tax expense		$ 15,546
Statutory income tax rate	35.00%	35.00%	35.00%
Non-deductible expenses, other	$ 9,048
Repayment of debt	3,714,044	$ 1,429,195	$ 525,909
Unrecognized tax benefits	0	$ 0	$ 0
Undistributed earnings	$ 1,600,000
Internal Revenue Service [Member]
Operating Loss Carryforwards [Line Items]
Statutory income tax rate	35.00%
Operating loss carryforwards	$ 32,157
Operating loss carryforwards, expiration date	Dec. 31, 2028
Foreign tax credits	$ 14,567
Canada Revenue Agency [Member]
Operating Loss Carryforwards [Line Items]
Foreign Statutory income tax rate	27.00%
Operating loss carryforwards	$ 14,269