Capital Transactions - Stock Compensation (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) item $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	May 07, 2019 shares
Share-Based Compensation
Options outstanding (in shares)	16,633	57,653	60,231
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Weighted average fair value of option grants | $ / shares	$ 44.87	$ 61.45	$ 48.65
Performance period	90 days
Compensation expenses
Stock based compensation expense | $	$ 8,685,000	$ 6,802,000	$ 10,274,000
Employee severance related costs | $			7,900,000
Forfeiture credit partially offset | $			$ 4,500,000
Number of Options
Outstanding at the beginning of the period (in shares)	57,653	60,231	300,580
Granted (in shares)	44,770	82,505	104,120
Exercised (in shares)	(41,020)	(2,578)	(232,514)
Cancelled (in shares)			(7,835)
Outstanding at the end of the period (in shares)	16,633	57,653	60,231
Exercisable (in shares)	16,633	57,653
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share) | $ / shares	$ 14.74	$ 14.74	$ 13.70
Exercised (in dollars per share) | $ / shares	14.78	14.78	13.36
Cancelled (in dollars per share) | $ / shares			15.86
Outstanding at the end of the period (in dollars per share) | $ / shares	14.62	14.74	$ 14.74
Exercisable (in dollars per share) | $ / shares	$ 14.62	$ 14.74
Weighted Average Remaining Contractual Term
Outstanding, Weighted Average Remaining Contractual Term (in years)	1 year	2 years 1 month 6 days
Exercisable, Weighted Average Remaining Contractual Term (in years)	1 year	2 years 1 month 6 days
Aggregate Intrinsic Value
Average intrinsic value of shares outstanding | $	$ 410,400	$ 1,474,500
Average intrinsic value of shares exercisable | $	$ 410,400	$ 1,474,500
Non-vested stock options
Non-vested shares at beginning of year (in shares)	237,977	284,686	575,781
Granted (in shares)	44,770	82,505	104,120
PSUs forfeited from the 2018 grant	(13,390)	(25,983)	(143,362)
Vested (in shares)	(69,184)	(103,231)	(251,853)
Non-vested shares at end of year (in shares)	200,173	237,977	284,686
Weighted Average Grant-Date Fair Value
Non-vested shares at beginning of year (in dollars per share) | $ / shares	$ 54.15	$ 45.21	$ 27.71
Granted (in dollars per share) | $ / shares	44.87	61.45	48.65
Forfeited (in dollars per share) | $ / shares	52.28	52.31	30.85
Vested (in dollars per share) | $ / shares	53.41	35.81	14.79
Non-vested shares at end of year (in dollars per share) | $ / shares	$ 52.45	$ 54.15	45.21
Director [Member]
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)	21,175	14,643
Granted (in dollars per share) | $ / shares	$ 44.87	$ 61.45	48.45
Number of shares
Granted (in shares)	21,175	14,643
Weighted Average Grant-Date Fair Value
Granted (in dollars per share) | $ / shares	$ 44.87	$ 61.45	$ 48.45
Number of Options
Granted (in shares)			18,576
Non-vested stock options
Granted (in shares)			18,576
Restricted stock grants and performance stock units
Compensation expenses
Total unrecognized compensation cost | $	$ 16,500,000
Unrecognized compensation cost recognized over a weighted average period (in years)	1 month 27 days
Employee Stock Option [Member]
Compensation expenses
Period from grant date after which stock options become exercisable, minimum (in months)	6 months
Period from grant date within which incentive stock options are exercisable, maximum (in years)	7 years
Aggregate Intrinsic Value
Total intrinsic value of options exercised | $	$ 1,800,000	$ 100,000	$ 10,500,000
Performance stock units
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)	157,210	69,132	87,864
Vesting period	3 years
Granted (in dollars per share) | $ / shares	$ 44.87	$ 61.45	$ 48.81
Number of performance period | item	2
Performance period	1 year
Award percentage	80.00%
Number of shares
Nonvested sharess at the beginning of the period (in shares)	196,609	233,571	370,917
Granted (in shares)	157,210	69,132	87,864
Additional shares awarded from the 2015 grant		83,042	67,853
Forfeited (in shares)	(11,392)	(23,052)	(89,481)
Vested (in shares)	(45,644)	(166,084)	(203,582)
Cancelled (in shares)	(3,991)
Nonvested shares at the end of the period (in shares)	292,792	196,609	233,571
Weighted Average Grant-Date Fair Value
Nonvested shares at the beginning of the period (in dollars per share) | $ / shares	$ 54.17	$ 45.44	$ 30.84
Granted (in dollars per share) | $ / shares	44.87	61.45	48.81
Additional shares awarded from the 2015 grant (in dollars per share) | $ / shares		35.81	14.80
Forfeiture (in dollars per share) | $ / shares	53.41
Vested (in dollars per share) | $ / shares	53.41	35.81	14.80
Cancelled (in dollars per share) | $ / shares	53.30	53.66	34.70
Nonvested shares at the end of the period (in dollars per share) | $ / shares	$ 49.39	$ 54.17	$ 45.44
Performance stock units | Maximum [Member]
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Award percentage	250.00%	200.00%	200.00%
Performance stock units | Minimum [Member]
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Award percentage	0.00%	0.00%	0.00%
Long Term Incentive Plan 2010 [Member]
Share-Based Compensation
Number of shares authorized				4,500,000
Shares remaining available for future issuance	3,800,000
Long Term Incentive Plan 2010 [Member] | Restricted Stock Units (RSUs) [Member]
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Vesting period	3 years
Granted (in dollars per share) | $ / shares	$ 44.87
Weighted Average Grant-Date Fair Value
Granted (in dollars per share) | $ / shares	$ 44.87
Long Term Incentive Plan 2010 [Member] | Restricted Stock Units (RSUs) [Member] | Director [Member]
Assumptions used to determine value of the shares purchased under the stock purchase plan using Black-Scholes option pricing model
Granted (in shares)	44,770
Number of shares
Granted (in shares)	44,770