Incentive Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation [Abstract]
Number of common shares available for grant under the incentive plan (in shares)	2,615,253
Share-based compensation	$ 23,993	$ 20,425	$ 24,345
Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation Cost			2,300
Tax benefits (expense) associated with stock-based compensation	$ 4,900	$ 5,300	$ 8,500
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Document Period End Date	Dec. 31, 2019
Stock awards vesting period	3 years
Employee Stock Purchase Plan (ESPP) [Abstract]
ESPP Stock Issued During Period (in shares)	29,000	30,000	38,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of shares vested during the year	$ 39,700	$ 1,200	$ 46,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 23,900
Unrecognized compensation expense, period for recognition (in months)	22 months
Equity Instruments Other than Options, Nonvested, Number of Shares[Roll Forward]
Balance at 12/31/2017 (in shares)	582,000
Granted (in shares)	200,000
Canceled (in shares)	(19,000)
Balance at 12/31/2018 (in shares)	443,000	582,000
Vested (in shares)	320,000
Weighted Average Grant Date Fair Value, Equity Instruments Other than Options [Abstract]
Balance at 12/31/2016 (in dollars per share)	$ 49.48
Granted (in dollars per share)	124.04	$ 65.98	$ 42.15
Vested (in dollars per share)	43.75
Canceled (in dollars per share)	77.83
Balance at 12/31/2017 (in dollars per share)	$ 86.10	$ 49.48
Restricted Stock [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards vesting period	3 years
Restricted Stock [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards vesting period	5 years
Performance Shares [Member]
Equity Instruments Other than Options, Nonvested, Number of Shares[Roll Forward]
Balance at 12/31/2017 (in shares)	426,000
Granted (in shares)	59,000
Canceled (in shares)	(6,000)
Balance at 12/31/2018 (in shares)	272,000	426,000
Vested (in shares)	207,000
Weighted Average Grant Date Fair Value, Equity Instruments Other than Options [Abstract]
Balance at 12/31/2016 (in dollars per share)	$ 46.35
Granted (in dollars per share)	139.71
Vested (in dollars per share)	29.57
Canceled (in dollars per share)	61.47
Balance at 12/31/2017 (in dollars per share)	$ 79.95	$ 46.35
Performance Shares [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards vesting period	3 years
2015LTIPAward [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Issued in Period (in shares)	352,000
Fair value of shares vested during the year	$ 45,100
2016LTIPAwards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 300
Equity Instruments Other than Options, Nonvested, Number of Shares[Roll Forward]
NumberofShareExpectedtoVestBasedOnCurrentEstimatesofPerformanceAchievment	211,000
2017LTIPAwards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 3,200
Equity Instruments Other than Options, Nonvested, Number of Shares[Roll Forward]
NumberofShareExpectedtoVestBasedOnCurrentEstimatesofPerformanceAchievment	130,000
2018LTIPAwards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options	$ 1,900
Equity Instruments Other than Options, Nonvested, Number of Shares[Roll Forward]
NumberofShareExpectedtoVestBasedOnCurrentEstimatesofPerformanceAchievment	21,000