Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Summary of Basic and Diluted Earnings per Share

The following table summarizes the basic and diluted earnings per share calculations:

	Year ended December 31,
	2016			2015			2014
	(in thousands except per share amounts)
Basic earnings per share:
Net income	$	75,810		$	90,100		$	194,544
Effect of participating securities—share-based    compensation awards		(1,333	)		(1,689	)		(1,830	)
Net income attributable to common shareholders	$	74,477		$	88,411		$	192,714
Diluted earnings per share:
Net income attributable to common shareholders	$	74,477		$	88,411		$	194,544
Interest on Exchangeable Notes, net of income taxes		8,719			8,468			8,456
Net income attributable to common diluted    shareholders	$	83,196		$	96,879		$	203,000
Weighted-average basic shares outstanding		68,642			74,446			73,495
Dilutive securities:
Shares issuable under share-based compensation    plan		—			423			298
Shares issuable pursuant to exchange of the    Exchangeable Notes		8,467			8,467			8,418
Diluted weighted-average number of shares    outstanding		77,109			83,336			82,211
Basic earnings per share	$	1.09		$	1.19		$	2.62
Diluted earnings per share	$	1.08		$	1.16		$	2.47

Summary of Potentially Dilutive Shares Excluded from Computation of Diluted Earnings Per Share

	Year ended December 31,
	2016		2015		2014
	(in thousands)
Shares issuable under share-based compensation    awards		701		369		371