Share-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Share-based compensation
Total compensation expense	$ 9,647		$ 9,439		$ 5,972
Income tax benefits	2,404		2,732		1,729
Performance share units
Share-based compensation
Stock options vesting period	3 years
Total compensation expense	6,263		6,860		3,658
Expense	3,182
Weighted average period (years)	1 year 3 months 18 days
Cash payment in settlement of Performance Share Unit Plan Units	5,914
Status of, and changes in, the Performance Share Unit Plan units granted to employees
Outstanding at the beginning of the period (in shares)	555,438
Granted (in shares)	160,021
Forfeited (in shares)	(4,774)
Exercised (in shares)	(189,390)
Outstanding at the end of the period (in shares)	521,295		555,438
Vested and expected to vest (in shares)	521,295
Lifeco
Share-based compensation
Number of trading days considered for determination of average closing price of common stock	20 days
Lifeco | Option
Share-based compensation
Period preceding the date of the grant, to determine exercise price of options granted	5 days
Options exercisable, term	10 years
Maximum period that retiring option holders can continue to exercise outstanding options	5 years
Total compensation expense	3,384		2,579		2,314
Expense	2,381
Weighted average period (years)	1 year 8 months 12 days
Granted (in shares)	539,400
Compensation expense to be recognized	2,984
Shares under option
Outstanding at the beginning of the period (in shares)	3,378,220
Granted (in shares)	539,400
Exercised (in shares)	(83,562)
Cancelled and Expired (in shares)	(40,400)
Outstanding at the end of the period (in shares)	3,793,658		3,378,220
Vested and expected to vest at the end of the period (in shares)	3,793,658
Exercisable at the end of the period (in shares)	2,533,642
Exercise price (Whole dollars)
Outstanding at the beginning of the period (in dollars per share)	$ 26.49
Granted (in dollars per share)	$ 26.86
Exercised (in dollars per share)	$ 22.85
Cancelled and Expired (in dollars per share)	$ 23.82
Outstanding at the end of the period (in dollars per share)	$ 24.69		$ 26.49
Vested and expected to vest at the end of the period (in dollars per share)	$ 24.69
Exercisable at the end of the period (in dollars per share)	$ 25.14
Remaining contractual term
Outstanding, December 31, 2014	5 years 9 months 18 days
Vested and expected to vest, December 31, 2014	5 years 9 months 18 days
Exercisable, December 31, 2014	4 years 9 months 18 days
Aggregate intrinsic value
Outstanding, December 31, 2014	17,409	[1]
Vested and expected to vest, December 31, 2014	17,409	[1]
Exercisable, December 31, 2014	10,877	[1]
Other information
Weighted average fair value of options granted (in dollars per share)	$ 5.53		$ 4.56		$ 3.47
Intrinsic value of options exercised	401	[2]	1,437	[2]	1,397	[2]
Fair value of options vested	$ 4,491		$ 1,843		$ 1,740
Weighted-average assumptions
Dividend yield	3.95%		4.53%		5.31%
Expected volatility	26.63%		26.73%		25.65%
Risk free interest rate	1.75%		1.38%		1.52%
Expected duration (years)	6 years 0 months		6 years 0 months		6 years 0 months
Lifeco | Performance share units
Share-based compensation
Number of shares considered for valuation of each stock award	1

[1] The aggregate intrinsic value is calculated as the difference between the market price of Lifeco common shares on December 31, 2014 and the exercise price of the option (only if the result is positive) multiplied by the number of options.

[2] The intrinsic value of options exercised is calculated as the difference between the market price of Lifeco common shares on the date of exercise and the exercise price of the option multiplied by the number of options exercised.