Stockholders' Equity - Repurchase Program (Details) - USD ($)				6 Months Ended			17 Months Ended
	Aug. 08, 2017	Jul. 27, 2017	Feb. 04, 2016	Jun. 30, 2017	Jun. 30, 2016	[1]	Jun. 30, 2017
Class of Stock [Line Items]
Shares repurchased (in shares)				411,166			1,670,311
Repurchase of common stock				$ 52,393,000	$ 26,037,000
Common Stock
Class of Stock [Line Items]
Stock repurchase program, approved amount			$ 500,000,000
Stock repurchase program, authorized time period			18 months
Repurchase agreements
Class of Stock [Line Items]
Shares repurchased							$ 240,100,000
Repurchase of common stock				$ 52,400,000
Subsequent Event | Common Stock
Class of Stock [Line Items]
Increase in authorized amount to be repurchased		$ 250,000,000
Period in force, extension of original period		18 months
Remaining authorized repurchase amount		$ 510,000,000
Scenario, Forecast | Common Stock
Class of Stock [Line Items]
Stock repurchased during period, value	$ 250,000,000
Stock repurchase program, number of shares authorized to be repurchased, percentage	85.00%

[1] Reflects the impact of the Company's adoption of Accounting Standards Update 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, to simplify several aspects of the accounting for share-based compensation, including the income tax consequences.