Stock-Based Compensation Plans (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) director $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) shares
Unrecognized compensation cost and vesting period
Unrecognized compensation costs related to unvested stock-based compensation arrangements	$ 7,700
Weighted-average period for recognition of unrecognized stock-based compensation expense	1 year 9 months 18 days
Other disclosures
Stock-based compensation expense recognized in operating expenses	$ 9,480	$ 10,356	$ 12,744
Requisite service period for options to vest	4 years
Tax benefit of stock-based compensation expense in provision for income taxes	$ 2,330	2,476	4,575
Share-based Payment Arrangement, Expense, after Tax	7,150	7,880	8,169
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value	16,760	15,372	11,043
Issuance of Company’s common stock	$ 0	$ 695	$ 6,610
Stock Bonus Plan
Other disclosures
Shares issued and committed to issue | shares	7,000	9,000,000	12,000
Stock-based compensation expense recognized in operating expenses	$ 800	$ 800	$ 1,200
Restricted Stock Units
Restricted stock unit activity
Outstanding at the beginning of the period (in shares) | shares	604,000
Awarded (in shares) | shares	220,660
Vested (in shares) | shares	(275,000)
Forfeited (in shares) | shares	(87,000)
Outstanding at the end of the period (in shares) | shares	462,000	604,000
Outstanding and expected to vest at the end of the period (in shares) | shares	458,000
Weighted-Average Exercise Price
Outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 41.37
Awarded (in dollars per share) | $ / shares	57.73
Vested (in dollars per share) | $ / shares	37.71
Forfeited (in dollars per share) | $ / shares	57.06
Outstanding at the end of the period (in dollars per share) | $ / shares	47.75	$ 41.37
Outstanding and expected to vest at the end of the period (in dollars per share) | $ / shares	$ 47.69
Aggregate Intrinsic Value
Outstanding at the end of the period (in dollars)	$ 37,065	$ 32,669
Outstanding and expected to vest at end of the period (in dollars)	$ 36,763
Closing price per share (in dollars per share) | $ / shares	$ 80.23
Total intrinsic value of awards vested (in dollars)	$ 16,700	$ 9,800	$ 10,800
Weighted-Average Exercise Price
Outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 41.37
Forfeited (in dollars per share) | $ / shares	57.06
Outstanding at the end of the period (in dollars per share) | $ / shares	$ 47.75	$ 41.37
Aggregate Intrinsic Value
Outstanding at the end of the period (in dollars)	$ 37,065	$ 32,669
Non-Qualified Stock Options | 2011 Plan
Stock-Based Compensation
Maximum common stock shares that may be issued under plan | shares	16,300,000
Independent directors | Restricted Stock Units
Aggregate Intrinsic Value
Number Of Directors | director	7
Foreign employees
Other disclosures
Shares issued and committed to issue | shares	4,000
Shares expected to be settled In cash | shares	3,000