Quarterly report pursuant to Section 13 or 15(d)

Earnings Per Share (Basic And Diluted Earnings Per Share) (Details)

v3.7.0.1
Earnings Per Share (Basic And Diluted Earnings Per Share) (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]          
Net income $ 32,774 $ 26,445 $ 54,021 $ 55,030 $ 118,708
Basic (shares) 52,495 52,394 52,464 52,386  
Dilutive effect of stock-based compensation awards, shares 280 547 334 544  
Diluted (shares) 52,775 52,941 52,798 52,930  
Basic (usd per share) $ 0.62 $ 0.50 $ 1.03 $ 1.05  
Diluted (usd per share) $ 0.62 $ 0.50 $ 1.02 $ 1.04  
Unexercised employee stock options and stock appreciation rights and unvested restricted stock units excluded from the diluted EPS calculation because their effect would have been antidilutive 3,755 1,849 3,784 1,884  
Accumulated Deficit [Member]          
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]          
Net income     $ 54,021   $ 118,708