Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2016

Summary of Significant Accounting Policies

Reconciliation of basic weighted average shares outstanding to diluted weighted average shares outstanding

	Three months ended September 30,		Nine months ended September 30,
	2015	2016	2015	2016
Basic weighted average number of shares outstanding	277,007	306,785	273,145	288,607
Add: Dilutive effect of non-vested restricted stock units	8	1,835	9	—
Add: Dilutive effect of outstanding stock options	—	—	—	—
Add: Dilutive effect of performance stock units	—	37	—	—
Diluted weighted average number of shares outstanding	277,015	308,657	273,154	288,607
Weighted average number of outstanding equity awards excluded from calculation of diluted earnings per common share(1):
Non-vested restricted stock and restricted stock units	2,483	1,251	2,240	6,899
Outstanding stock options	743	693	492	706
Performance stock units	—	660	—	577

(1)   The potential dilutive effects of these awards were excluded from the computation of earnings per common share—assuming dilution because the inclusion of these awards would have been anti-dilutive.

Summary of adjustments from early adoption of new accounting pronouncement

	As Previously Reported				As Adjusted
	Nine Months Ended September 30, 2015		Adjustment Effect		Nine Months Ended September 30, 2015
Changes in accrued liabilities	$	29,537		4,554		34,091
Employee tax withholding for settlement of equity compensation awards		—		(4,554)		(4,554)